path: root/doc/rfc/rfc4108.txt

Network Working Group                                         R. Housley
Request for Comments: 4108                                Vigil Security
Category: Standards Track                                    August 2005


 Using Cryptographic Message Syntax (CMS) to Protect Firmware Packages

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2005).

Abstract

   This document describes the use of the Cryptographic Message Syntax
   (CMS) to protect firmware packages, which provide object code for one
   or more hardware module components.  CMS is specified in RFC 3852.  A
   digital signature is used to protect the firmware package from
   undetected modification and to provide data origin authentication.
   Encryption is optionally used to protect the firmware package from
   disclosure, and compression is optionally used to reduce the size of
   the protected firmware package.  A firmware package loading receipt
   can optionally be generated to acknowledge the successful loading of
   a firmware package.  Similarly, a firmware package load error report
   can optionally be generated to convey the failure to load a firmware
   package.


















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Table of Contents

   1. Introduction ....................................................3
      1.1. Terminology ................................................5
      1.2. Architectural Elements .....................................5
           1.2.1. Hardware Module Requirements ........................7
           1.2.2. Firmware Package Requirements .......................8
           1.2.3. Bootstrap Loader Requirements .......................9
                  1.2.3.1. Legacy Stale Version Processing ...........11
                  1.2.3.2. Preferred Stale Version Processing ........12
           1.2.4. Trust Anchors ......................................12
           1.2.5. Cryptographic and Compression Algorithm
                  Requirements .......................................13
      1.3. Hardware Module Security Architecture .....................14
      1.4. ASN.1 Encoding ............................................14
      1.5. Protected Firmware Package Loading ........................15
   2. Firmware Package Protection ....................................15
      2.1. Firmware Package Protection CMS Content Type Profile ......18
           2.1.1. ContentInfo ........................................18
           2.1.2. SignedData .........................................18
                  2.1.2.1. SignerInfo ................................19
                  2.1.2.2. EncapsulatedContentInfo ...................20
           2.1.3. EncryptedData ......................................20
                  2.1.3.1. EncryptedContentInfo ......................21
           2.1.4. CompressedData .....................................21
                  2.1.4.1. EncapsulatedContentInfo ...................22
           2.1.5. FirmwarePkgData ....................................22
      2.2. Signed Attributes .........................................22
           2.2.1. Content Type .......................................23
           2.2.2. Message Digest .....................................24
           2.2.3. Firmware Package Identifier ........................24
           2.2.4. Target Hardware Module Identifiers .................25
           2.2.5. Decrypt Key Identifier .............................26
           2.2.6. Implemented Crypto Algorithms ......................26
           2.2.7. Implemented Compression Algorithms .................27
           2.2.8. Community Identifiers ..............................27
           2.2.9. Firmware Package Information .......................29
           2.2.10. Firmware Package Message Digest ...................30
           2.2.11. Signing Time ......................................30
           2.2.12. Content Hints .....................................31
           2.2.13. Signing Certificate ...............................31
      2.3. Unsigned Attributes .......................................32
           2.3.1. Wrapped Firmware Decryption Key ....................33
   3. Firmware Package Load Receipt ..................................34
      3.1. Firmware Package Load Receipt CMS Content Type Profile ....36
           3.1.1. ContentInfo ........................................36





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           3.1.2. SignedData .........................................36
                  3.1.2.1. SignerInfo ................................37
                  3.1.2.2. EncapsulatedContentInfo ...................38
           3.1.3. FirmwarePackageLoadReceipt .........................38
      3.2. Signed Attributes .........................................40
           3.2.1. Content Type .......................................40
           3.2.2. Message Digest .....................................40
           3.2.3. Signing Time .......................................40
   4. Firmware Package Load Error ....................................41
      4.1. Firmware Package Load Error CMS Content Type Profile ......42
           4.1.1. ContentInfo ........................................42
           4.1.2. SignedData .........................................43
                  4.1.2.1. SignerInfo ................................43
                  4.1.2.2. EncapsulatedContentInfo ...................43
           4.1.3. FirmwarePackageLoadError ...........................43
      4.2. Signed Attributes .........................................49
           4.2.1. Content Type .......................................49
           4.2.2. Message Digest .....................................49
           4.2.3. Signing Time .......................................50
   5. Hardware Module Name ...........................................50
   6. Security Considerations ........................................51
      6.1. Cryptographic Keys and Algorithms .........................51
      6.2. Random Number Generation ..................................51
      6.3. Stale Firmware Package Version Number .....................52
      6.4. Community Identifiers .....................................53
   7. References .....................................................54
      7.1. Normative References ......................................54
      7.2. Informative References ....................................54
   Appendix A: ASN.1 Module ..........................................56

1.  Introduction

   This document describes the use of the Cryptographic Message Syntax
   (CMS) [CMS] to protect firmware packages.  This document also
   describes the use of CMS for receipts and error reports for firmware
   package loading.  The CMS is a data protection encapsulation syntax
   that makes use of ASN.1 [X.208-88, X.209-88].  The protected firmware
   package can be associated with any particular hardware module;
   however, this specification was written with the requirements of
   cryptographic hardware modules in mind, as these modules have strong
   security requirements.

   The firmware package contains object code for one or more
   programmable components that make up the hardware module.  The
   firmware package, which is treated as an opaque binary object, is
   digitally signed.  Optional encryption and compression are also
   supported.  When all three are used, the firmware package is
   compressed, then encrypted, and then signed.  Compression simply



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   reduces the size of the firmware package, allowing more efficient
   processing and transmission.  Encryption protects the firmware
   package from disclosure, which allows transmission of sensitive
   firmware packages over insecure links.  The encryption algorithm and
   mode employed may also provide integrity, protecting the firmware
   package from undetected modification.  The encryption protects
   proprietary algorithms, classified algorithms, trade secrets, and
   implementation techniques.  The digital signature protects the
   firmware package from undetected modification and provides data
   origin authentication.  The digital signature allows the hardware
   module to confirm that the firmware package comes from an acceptable
   source.

   If encryption is used, the firmware-decryption key must be made
   available to the hardware module via a secure path.  The key might be
   delivered via physical media or via an independent electronic path.
   One optional mechanism for distributing the firmware-decryption key
   is specified in Section 2.3.1, but any secure key distribution
   mechanism is acceptable.

   The signature verification public key must be made available to the
   hardware module in a manner that preserves its integrity and confirms
   its source.  CMS supports the transfer of certificates, and this
   facility can be used to transfer a certificate that contains the
   signature verification public key (a firmware-signing certificate).
   However, use of this facility introduces a level of indirection.
   Ultimately, a trust anchor public key must be made available to the
   hardware module.  Section 1.2 establishes a requirement that the
   hardware module store one or more trust anchors.

   Hardware modules may not be capable of accessing certificate
   repositories or delegated path discovery (DPD) servers [DPD&DPV] to
   acquire certificates needed to complete a certification path.  Thus,
   it is the responsibility of the firmware package signer to include
   sufficient certificates to enable each module to validate the
   firmware-signer certificate (see Section 2.1.2).  Similarly, hardware
   modules may not be capable of accessing a certificate revocation list
   (CRL) repository, an OCSP responder [OCSP], or a delegated path
   validation (DPV) server [DPD&DPV] to acquire revocation status
   information.  Thus, if the firmware package signature cannot be
   validated solely with the trust anchor public key and the hardware
   module is not capable of performing full certification path
   validation, then it is the responsibility of the entity loading a
   package into a hardware module to validate the firmware-signer
   certification path prior to loading the package into a hardware
   module.  The means by which this external certificate revocation
   status checking is performed is beyond the scope of this
   specification.



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   Hardware modules will only accept firmware packages with a valid
   digital signature.  The signature is either validated directly using
   the trust anchor public key or using a firmware-signer certification
   path that is validated to the trust anchor public key.  Thus, the
   trust anchors define the set of entities that can create firmware
   packages for the hardware module.

   The disposition of a previously loaded firmware package after the
   successful validation of another firmware package is beyond the scope
   of this specification.  The amount of memory available to the
   hardware module will determine the range of alternatives.

   In some cases, hardware modules can generate receipts to acknowledge
   the loading of a particular firmware package.  Such receipts can be
   used to determine which hardware modules need to receive an updated
   firmware package whenever a flaw in an earlier firmware package is
   discovered.  Hardware modules can also generate error reports to
   indicate the unsuccessful firmware package loading.  To implement
   either receipt or error report generation, the hardware module is
   required to have a unique permanent serial number.  Receipts and
   error reports can be either signed or unsigned.  To generate
   digitally signed receipts or error reports, a hardware module MUST be
   issued its own private signature key and a certificate that contains
   the corresponding signature validation public key.  In order to save
   memory with the hardware module, the hardware module might store a
   certificate designator instead of the certificate itself.  The
   private signature key requires secure storage.

1.1.  Terminology

   In this document, the key words MUST, MUST NOT, REQUIRED, SHOULD,
   SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL are to be interpreted as
   described in [STDWORDS].

1.2.  Architectural Elements

   The architecture includes the hardware module, the firmware package,
   and a bootstrap loader.  The bootstrap loader MUST have access to one
   or more trusted public keys, called trust anchors, to validate the
   signature on the firmware package.  If a signed firmware package load
   receipt or error report is created on behalf of the hardware module,
   then the bootstrap loader MUST have access to a private signature key
   to generate the signature and the signer identifier for the
   corresponding signature validation certificate or its designator.  A
   signature validation certificate MAY be included to aid signature
   validation.  To implement this optional capability, the hardware
   module MUST have a unique serial number and a private signature key;
   the hardware module MAY also include a certificate that contains the



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   corresponding signature validation public key.  These items MUST be
   installed in the hardware module before it is deployed.  The private
   key and certificate can be generated and installed as part of the
   hardware module manufacture process.  Figure 1 illustrates these
   architectural elements.

   ASN.1 object identifiers are the preferred means of naming the
   architectural elements.

   Details of managing the trust anchors are beyond the scope of this
   specification.  However, one or more trust anchors MUST be installed
   in the hardware module using a secure process before it is deployed.
   These trust anchors provide a means of controlling the acceptable
   sources of firmware packages.  The hardware module vendor can include
   provisions for secure, remote management of trust anchors.  One
   approach is to include trust anchors in the firmware packages
   themselves.  This approach is analogous to the optional capability
   described later for updating the bootstrap loader.

   In a cryptographic hardware module, the firmware package might
   implement many different cryptographic algorithms.

   When the firmware package is encrypted, the firmware-decryption key
   and the firmware package MUST both be provided to the hardware
   module.  The firmware-decryption key is necessary to use the
   associated firmware package.  Generally, separate distribution
   mechanisms will be employed for the firmware-decryption key and the
   firmware package.  An optional mechanism for securely distributing
   the firmware-decryption key with the firmware package is specified in
   Section 2.3.1.





















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            +------------------------------------------------------+
            |  Hardware Module                                     |
            |                                                      |
            |   +---------------+   +--------------------------+   |
            |   |  Bootstrap    |   |  Firmware Package        |   |
            |   |  Loader       |   |                          |   |
            |   +---------------+   |   +------------------+   |   |
            |                       |   : Firmware Package :   |   |
            |   +---------------+   |   : Identifier and   :   |   |
            |   |  Trust        |   |   : Version Number   :   |   |
            |   |  Anchor(s)    |   |   +------------------+   |   |
            |   +---------------+   |                          |   |
            |                       |   +-------------+        |   |
            |   +---------------+   |   : Algorithm 1 :        |   |
            |   |  Serial Num.  |   |   +-+-----------+-+      |   |
            |   +---------------+   |     : Algorithm 2 :      |   |
            |                       |     +-+-----------+-+    |   |
            |   +---------------+   |       : Algorithm n :    |   |
            |   |  Hardware     |   |       +-------------+    |   |
            |   |  Module Type  |   |                          |   |
            |   +---------------+   +--------------------------+   |
            |                                                      |
            |        +------------------------------------+        |
            |        |  Optional Private Signature Key &  |        |
            |        |  Signature Validation Certificate  |        |
            |        |  or the Certificate Designator     |        |
            |        +------------------------------------+        |
            |                                                      |
            +------------------------------------------------------+

                     Figure 1.  Architectural Elements

1.2.1.  Hardware Module Requirements

   Many different vendors develop hardware modules, and each vendor
   typically identifies its modules by product type (family) and
   revision level.  A unique object identifier MUST name each hardware
   module type and revision.

   Each hardware module within a hardware module family SHOULD have a
   unique permanent serial number.  However, if the optional receipt or
   error report generation capability is implemented, then the hardware
   module MUST have a unique permanent serial number.  If the optional
   receipt or error report signature capability is implemented, then the
   hardware module MUST have a private signature key and a certificate
   containing the corresponding public signature validation key or its
   designator.  If a serial number is present, the bootstrap loader uses




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   it for authorization decisions (see Section 2.2.8), receipt
   generation (see Section 3), and error report generation (see
   Section 4).

   When the hardware module includes more than one firmware-programmable
   component, the bootstrap loader distributes components of the package
   to the appropriate components within the hardware module after the
   firmware package is validated.  The bootstrap loader is discussed
   further in Section 1.2.3.

1.2.2.  Firmware Package Requirements

   Two approaches to naming firmware packages are supported: legacy and
   preferred.  Firmware package names are placed in a CMS signed
   attribute, not in the firmware package itself.

   Legacy firmware package names are simply octet strings, and no
   structure is assumed.  This firmware package name form is supported
   in order to facilitate existing configuration management systems.  We
   assume that the firmware signer and the bootstrap loader will
   understand any internal structure to the octet string.  In
   particular, given two legacy firmware package names, we assume that
   the firmware signer and the bootstrap loader will be able to
   determine which one represents the newer version of the firmware
   package.  This capability is necessary to implement the stale version
   feature.  If a firmware package with a disastrous flaw is released,
   subsequent firmware package versions MAY designate a stale legacy
   firmware package name in order to prevent subsequent rollback to the
   stale version or versions earlier than the stale version.

   Preferred firmware package names are a combination of the firmware
   package object identifier and a version number.  A unique object
   identifier MUST identify the collection of features that characterize
   the firmware package.  For example, firmware packages for a cable
   modem and a wireless LAN network interface card warrant distinct
   object identifiers.  Similarly, firmware packages that implement
   distinct suites of cryptographic algorithms and modes of operation,
   or that emulate different (non-programmable) cryptographic devices
   warrant distinct object identifiers.  The version number MUST
   identify a particular build or release of the firmware package.  The
   version number MUST be a monotonically increasing non-negative
   integer.  Generally, an earlier version is replaced with a later one.
   If a firmware package with a disastrous flaw is released, subsequent
   firmware package versions MAY designate a stale version number to
   prevent subsequent rollback to the stale version or versions earlier
   than the stale version.





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   Firmware packages are developed to run on one or more hardware module
   type.  The firmware package digital signature MUST bind the list of
   supported hardware module object identifiers to the firmware package.

   In many cases, the firmware package signature will be validated
   directly with the trust anchor public key, avoiding the need to
   construct certification paths.  Alternatively, the trust anchor can
   delegate firmware package signing to another public key through a
   certification path.  In the latter case, the firmware package SHOULD
   contain the certificates needed to construct the certification path
   that begins with a certificate issued by the trust anchors and ends
   with a certificate issued to the firmware package signer.

   The firmware package MAY contain a list of community identifiers.
   These identifiers name the hardware modules that are authorized to
   load the firmware package.  If the firmware package contains a list
   of community identifiers, then the bootstrap loader MUST reject the
   firmware package if the hardware module is not a member of one of the
   identified communities.

   When a hardware module includes multiple programmable components, the
   firmware package SHOULD contain executable code for all of the
   components.  Internal tagging within the firmware package MUST tell
   the bootstrap loader which portion of the overall firmware package is
   intended for each component; however, this tagging is expected to be
   specific to each hardware module.  Because this specification treats
   the firmware package as an opaque binary object, the format of the
   firmware package is beyond the scope of this specification.

1.2.3.  Bootstrap Loader Requirements

   The bootstrap loader MUST have access to a physical interface and any
   related driver or protocol software necessary to obtain a firmware
   package.  The same interface SHOULD be used to deliver receipts and
   error reports.  Details of the physical interface as well as the
   driver or protocol software are beyond the scope of this
   specification.

   The bootstrap loader can be a permanent part of the hardware module,
   or it can be replaced by loading a firmware package.  In Figure 1,
   the bootstrap loader is implemented as separate logic within the
   hardware module.  Not all hardware modules will include the ability
   to replace or update the bootstrap loader, and this specification
   does not mandate such support.

   If the bootstrap loader can be loaded by a firmware package, an
   initial bootstrap loader MUST be installed in non-volatile memory
   prior to deployment.  All bootstrap loaders, including an initial



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   bootstrap loader if one is employed, MUST meet the requirements in
   this section.  However, the firmware package containing the bootstrap
   loader MAY also contain other routines.

   The bootstrap loader requires access to cryptographic routines.
   These routines can be implemented specifically for the bootstrap
   loader, or they can be shared with other hardware module features.
   The bootstrap loader MUST have access to a one-way hash function and
   digital signature verification routines to validate the digital
   signature on the firmware package and to validate the certification
   path for the firmware-signing certificate.

   If firmware packages are encrypted, the bootstrap loader MUST have
   access to a decryption routine.  Access to a corresponding encryption
   function is not required, since hardware modules need not be capable
   of generating firmware packages.  Because some symmetric encryption
   algorithm implementations (such as AES [AES]) employ separate logic
   for encryption and decryption, some hardware module savings might
   result.

   If firmware packages are compressed, the bootstrap loader MUST also
   have access to a decompression function.  This function can be
   implemented specifically for the bootstrap loader, or it can be
   shared with other hardware module features.  Access to a
   corresponding compression function is not required, since hardware
   modules need not be capable of generating firmware packages.

   If the optional receipt generation or error report capability is
   supported, the bootstrap loader MUST have access to the hardware
   module serial number and the object identifier for the hardware
   module type.  If the optional signed receipt generation or signed
   error report capability is supported, the bootstrap loader MUST also
   have access to a one-way hash function and digital signature
   routines, the hardware module private signing key, and the
   corresponding signature validation certificate or its designator.

   The bootstrap loader requires access to one or more trusted public
   keys, called trust anchors, to validate the firmware package digital
   signature.  One or more trust anchors MUST be installed in non-
   volatile memory prior to deployment.  The bootstrap loader MUST
   reject a firmware package if it cannot validate the signature, which
   MAY require the construction of a valid certification path from the
   firmware-signing certificate to one of the trust anchors [PROFILE].
   However, in many cases, the firmware package signature will be
   validated directly with the trust anchor public key, avoiding the
   need to construct certification paths.





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   The bootstrap loader MUST reject a firmware package if the list of
   supported hardware module type identifiers within the firmware
   package does not include the object identifier of the hardware
   module.

   The bootstrap loader MUST reject a firmware package if the firmware
   package includes a list of community identifiers and the hardware
   module is not a member of one of the listed communities.  The means
   of determining community membership is beyond the scope of this
   specification.

   The bootstrap loader MUST reject a firmware package if it cannot
   successfully decrypt the firmware package using the firmware-
   decryption key available to the hardware module.  The firmware
   package contains an identifier of the firmware-decryption key needed
   for decryption.

   When an earlier version of a firmware package is replacing a later
   one, the bootstrap loader SHOULD generate a warning.  The manner in
   which a warning is generated is highly dependent on the hardware
   module and the environment in which it is being used.  If a firmware
   package with a disastrous flaw is released and subsequent firmware
   package versions designate a stale version, the bootstrap loader
   SHOULD prevent loading of the stale version and versions earlier than
   the stale version.

1.2.3.1.  Legacy Stale Version Processing

   In case a firmware package with a disastrous flaw is released,
   subsequent firmware package versions that employ the legacy firmware
   package name form MAY include a stale legacy firmware package name to
   prevent subsequent rollback to the stale version or versions earlier
   than the stale version.  As described in the Security Considerations
   section of this document, the inclusion of a stale legacy firmware
   package name in a firmware package cannot completely prevent
   subsequent use of the stale firmware package.  However, many hardware
   modules are expected to have very few firmware packages written for
   them, allowing the stale firmware package version feature to provide
   important protections.

   Non-volatile storage for stale version numbers is needed.  The number
   of stale legacy firmware package names that can be stored depends on
   the amount of storage that is available.  When a firmware package is
   loaded and it contains a stale legacy firmware package name, then it
   SHOULD be added to a list kept in non-volatile storage.  When
   subsequent firmware packages are loaded, the legacy firmware package





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   name of the new package is compared to the list in non-volatile
   storage.  If the legacy firmware package name represents the same
   version or an older version of a member of the list, then the new
   firmware packages SHOULD be rejected.

   The amount of non-volatile storage that needs to be dedicated to
   saving legacy firmware package names and stale legacy firmware
   packages names depends on the number of firmware packages that are
   likely to be developed for the hardware module.

1.2.3.2.  Preferred Stale Version Processing

   If a firmware package with a disastrous flaw is released, subsequent
   firmware package versions that employ preferred firmware package name
   form MAY include a stale version number to prevent subsequent
   rollback to the stale version or versions earlier than the stale
   version.  As described in the Security Considerations section of this
   document, the inclusion of a stale version number in a firmware
   package cannot completely prevent subsequent use of the stale
   firmware package.  However, many hardware modules are expected to
   have very few firmware packages written for them, allowing the stale
   firmware package version feature to provide important protections.

   Non-volatile storage for stale version numbers is needed.  The number
   of stale version numbers that can be stored depends on the amount of
   storage that is available.  When a firmware package is loaded and it
   contains a stale version number, then the object identifier of the
   firmware package and the stale version number SHOULD be added to a
   list that is kept in non-volatile storage.  When subsequent firmware
   packages are loaded, the object identifier and version number of the
   new package are compared to the list in non-volatile storage.  If the
   object identifier matches and the version number is less than or
   equal to the stale version number, then the new firmware packages
   SHOULD be rejected.

   The amount of non-volatile storage that needs to be dedicated to
   saving firmware package identifiers and stale version numbers depends
   on the number of firmware packages that are likely to be developed
   for the hardware module.

1.2.4.  Trust Anchors

   A trust anchor MUST consist of a public key signature algorithm and
   an associated public key, which MAY optionally include parameters.  A
   trust anchor MUST also include a public key identifier.  A trust
   anchor MAY also include an X.500 distinguished name.





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   The trust anchor public key is used in conjunction with the signature
   validation algorithm in two different ways.  First, the trust anchor
   public key is used directly to validate the firmware package
   signature.  Second, the trust anchor public key is used to validate
   an X.509 certification path, and then the subject public key in the
   final certificate in the certification path is used to validate the
   firmware package signature.

   The public key names the trust anchor, and each public key has a
   public key identifier.  The public key identifier identifies the
   trust anchor as the signer when it is used directly to validate
   firmware package signatures.  This key identifier can be stored with
   the trust anchor, or it can be computed from the public key whenever
   needed.

   The optional trusted X.500 distinguished name MUST be present in
   order for the trust anchor public key to be used to validate an X.509
   certification path.  Without an X.500 distinguished name,
   certification path construction cannot use the trust anchor.

1.2.5.  Cryptographic and Compression Algorithm Requirements

   A firmware package for a cryptographic hardware module includes
   cryptographic algorithm implementations.  In addition, a firmware
   package for a non-cryptographic hardware module will likely include
   cryptographic algorithm implementations to support the bootstrap
   loader in the validation of firmware packages.

   A unique algorithm object identifier MUST be assigned for each
   cryptographic algorithm and mode implemented by a firmware package.
   A unique algorithm object identifier MUST also be assigned for each
   compression algorithm implemented by a firmware package.  The
   algorithm object identifiers can be used to determine whether a
   particular firmware package satisfies the needs of a particular
   application.  To facilitate the development of algorithm-agile
   applications, the cryptographic module interface SHOULD allow
   applications to query the cryptographic module for the object
   identifiers associated with each cryptographic algorithm contained in
   the currently loaded firmware package.  Applications SHOULD also be
   able to query the cryptographic module to determine attributes
   associated with each algorithm.  Such attributes might include the
   algorithm type (symmetric encryption, asymmetric encryption, key
   agreement, one-way hash function, digital signature, and so on), the
   algorithm block size or modulus size, and parameters for asymmetric
   algorithms.  This specification does not establish the conventions
   for the retrieval of algorithm identifiers or algorithm attributes.





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1.3.  Hardware Module Security Architecture

   The bootstrap loader MAY be permanently stored in read-only memory or
   separately loaded into non-volatile memory as discussed above.

   In most hardware module designs, the firmware package execution
   environment offers a single address space.  If it does, the firmware
   package SHOULD contain a complete firmware package load for the
   hardware module.  In this situation, the firmware package does not
   contain a partial or incremental set of functions.  A complete
   firmware package load will minimize complexity and avoid potential
   security problems.  From a complexity perspective, the incremental
   loading of packages makes it necessary for each package to identify
   any other packages that are required (its dependencies), and the
   bootstrap loader needs to verify that all of the dependencies are
   satisfied before attempting to execute the firmware package.  When a
   hardware module is based on a general purpose processor or a digital
   signal processor, it is dangerous to allow arbitrary packages to be
   loaded simultaneously unless there is a reference monitor to ensure
   that independent portions of the code cannot interfere with one
   another.  Also, it is difficult to evaluate arbitrary combinations of
   software modules [SECREQMTS].  For these reasons, a complete firmware
   package load is RECOMMENDED; however, this specification allows the
   firmware signer to identify dependencies between firmware packages in
   order to handle all situations.

   The firmware packages MAY have dependencies on routines provided by
   other firmware packages.  To minimize the security evaluation
   complexity of a hardware module employing such a design, the firmware
   package MUST identify the package identifiers (and the minimum
   version numbers when the preferred firmware package name form is
   used) of the packages upon which it depends.  The bootstrap loader
   MUST reject a firmware package load if it contains a dependency on a
   firmware package that is not available.

   Loading a firmware package can impact the satisfactory resolution of
   dependencies of other firmware packages that are already part of the
   hardware module configuration.  For this reason, the bootstrap loader
   MUST reject the loading of a firmware package if the dependencies of
   any firmware package in the resulting configurations will be
   unsatisfied.

1.4.  ASN.1 Encoding

   The CMS uses Abstract Syntax Notation One (ASN.1) [X.208-88,
   X.209-88].  ASN.1 is a formal notation used for describing data
   protocols, regardless of the programming language used by the
   implementation.  Encoding rules describe how the values defined in



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   ASN.1 will be represented for transmission.  The Basic Encoding Rules
   (BER) are the most widely employed rule set, but they offer more than
   one way to represent data structures.  For example, definite length
   encoding and indefinite length encoding are supported.  This
   flexibility is not desirable when digital signatures are used.  As a
   result, the Distinguished Encoding Rules (DER) [X.509-88] were
   invented.  DER is a subset of BER that ensures a single way to
   represent a given value.  For example, DER always employs definite
   length encoding.

   In this specification, digitally signed structures MUST be encoded
   with DER.  Other structures do not require DER, but the use of
   definite length encoding is strongly RECOMMENDED.  By always using
   definite length encoding, the bootstrap loader will have fewer
   options to implement.  In situations where there is very high
   confidence that only definite length encoding will be used, support
   for indefinite length decoding MAY be omitted.

1.5.  Protected Firmware Package Loading

   This document does not attempt to specify a physical interface, any
   related driver software, or a protocol necessary for loading firmware
   packages.  Many different delivery mechanisms are envisioned,
   including portable memory devices, file transfer, and web pages.
   Section 2 of this specification defines the format that MUST be
   presented to the hardware module regardless of the interface that is
   used.  This specification also specifies the format of the response
   that MAY be generated by the hardware module.  Section 3 of this
   specification defines the format that MAY be returned by the hardware
   module when a firmware package loads successfully.  Section 4 of this
   specification defines the format that MAY be returned by the hardware
   module when a firmware package load is unsuccessful.  The firmware
   package load receipts and firmware package load error reports can be
   either signed or unsigned.

2.  Firmware Package Protection

   The Cryptographic Message Syntax (CMS) is used to protect a firmware
   package, which is treated as an opaque binary object.  A digital
   signature is used to protect the firmware package from undetected
   modification and to provide data origin authentication.  Encryption
   is optionally used to protect the firmware package from disclosure,
   and compression is optionally used to reduce the size of the
   protected firmware package.  The CMS ContentInfo content type MUST
   always be present, and it MUST encapsulate the CMS SignedData content
   type.  If the firmware package is encrypted, then the CMS SignedData
   content type MUST encapsulate the CMS EncryptedData content type.  If
   the firmware package is compressed, then either the CMS SignedData



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   content type (when encryption is not used) or the CMS EncryptedData
   content type (when encryption is used) MUST encapsulate the CMS
   CompressedData content type.  Finally, (1) the CMS SignedData content
   type (when neither encryption nor compression is used), (2) the CMS
   EncryptedData content type (when encryption is used, but compression
   is not), or (3) the CMS CompressedData content type (when compression
   is used) MUST encapsulate the simple firmware package using the
   FirmwarePkgData content type defined in this specification (see
   Section 2.1.5).

   The firmware package protection is summarized as follows (see [CMS]
   for the full syntax):

      ContentInfo {
        contentType          id-signedData, -- (1.2.840.113549.1.7.2)
        content              SignedData
      }

      SignedData {
        version              CMSVersion, -- always set to 3
        digestAlgorithms     DigestAlgorithmIdentifiers, -- Only one
        encapContentInfo     EncapsulatedContentInfo,
        certificates         CertificateSet, -- Signer cert. path
        crls                 CertificateRevocationLists, -- Optional
        signerInfos          SET OF SignerInfo -- Only one
      }

      SignerInfo {
        version              CMSVersion, -- always set to 3
        sid                  SignerIdentifier,
        digestAlgorithm      DigestAlgorithmIdentifier,
        signedAttrs          SignedAttributes, -- Required
        signatureAlgorithm   SignatureAlgorithmIdentifier,
        signature            SignatureValue,
        unsignedAttrs        UnsignedAttributes -- Optional
      }















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      EncapsulatedContentInfo {
        eContentType         id-encryptedData, -- (1.2.840.113549.1.7.6)
                             -- OR --
                             id-ct-compressedData,
                                       -- (1.2.840.113549.1.9.16.1.9)
                             -- OR --
                             id-ct-firmwarePackage,
                                       -- (1.2.840.113549.1.9.16.1.16)
        eContent             OCTET STRING
      }                            -- Contains EncryptedData OR
                                   -- CompressedData OR
                                   -- FirmwarePkgData

      EncryptedData {
        version              CMSVersion, -- Always set to 0
        encryptedContentInfo EncryptedContentInfo,
        unprotectedAttrs     UnprotectedAttributes -- Omit
      }

      EncryptedContentInfo {
        contentType          id-ct-compressedData,
                                       -- (1.2.840.113549.1.9.16.1.9)
                             -- OR --
                             id-ct-firmwarePackage,
                                       -- (1.2.840.113549.1.9.16.1.16)
        contentEncryptionAlgorithm ContentEncryptionAlgorithmIdentifier,
        encryptedContent OCTET STRING
      }                                -- Contains CompressedData OR
                                       -- FirmwarePkgData

      CompressedData {
        version              CMSVersion, -- Always set to 0
        compressionAlgorithm CompressionAlgorithmIdentifier,
        encapContentInfo     EncapsulatedContentInfo
      }

      EncapsulatedContentInfo {
        eContentType         id-ct-firmwarePackage,
                                         -- (1.2.840.113549.1.9.16.1.16)
        eContent             OCTET STRING -- Contains FirmwarePkgData
      }

      FirmwarePkgData         OCTET STRING -- Contains firmware package








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2.1.  Firmware Package Protection CMS Content Type Profile

   This section specifies the conventions for using the CMS ContentInfo,
   SignedData, EncryptedData, and CompressedData content types.  It also
   defines the FirmwarePkgData content type.

2.1.1.  ContentInfo

   The CMS requires that the outermost encapsulation be ContentInfo
   [CMS].  The fields of ContentInfo are used as follows:

      contentType indicates the type of the associated content, and in
         this case, the encapsulated type is always SignedData.  The
         id-signedData (1.2.840.113549.1.7.2) object identifier MUST be
         present in this field.

      content holds the associated content, and in this case, the
         content field MUST contain SignedData.

2.1.2.  SignedData

   The SignedData content type [CMS] contains the signed firmware
   package (which might be compressed, encrypted, or compressed and then
   encrypted prior to signature), the certificates needed to validate
   the signature, and one digital signature value.  The fields of
   SignedData are used as follows:

   version is the syntax version number, and in this case, it MUST be
      set to 3.

   digestAlgorithms is a collection of message digest algorithm
      identifiers, and in this case, it MUST contain a single message
      digest algorithm identifier.  The message digest algorithm
      employed by the firmware package signer MUST be present.

   encapContentInfo contains the signed content, consisting of a content
      type identifier and the content itself.  The use of the
      EncapsulatedContentInfo type is discussed further in Section
      2.1.2.2.

   certificates is an optional collection of certificates.  If the trust
      anchor signed the firmware package directly, then certificates
      SHOULD be omitted.  If it did not, then certificates SHOULD
      include the X.509 certificate of the firmware package signer.  The
      set of certificates SHOULD be sufficient for the bootstrap loader
      to construct a certification path from the trust anchor to the
      firmware-signer's certificate.  PKCS#6 extended certificates




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      [PKCS#6] and attribute certificates (either version 1 or
      version 2) [X.509-97, X.509-00, ACPROFILE] MUST NOT be included in
      the set of certificates.

   crls is an optional collection of certificate revocation lists
      (CRLs), and in this case, CRLs SHOULD NOT be included by the
      firmware package signer.  It is anticipated that firmware packages
      may be generated, signed, and made available in repositories for
      downloading into hardware modules.  In such contexts, it would be
      difficult for the firmware package signer to include timely CRLs
      in the firmware package.  However, because the CRLs are not
      covered by the signature, timely CRLs MAY be inserted by some
      other party before the firmware package is delivered to the
      hardware module.

   signerInfos is a collection of per-signer information, and in this
      case, the collection MUST contain exactly one SignerInfo.  The use
      of the SignerInfo type is discussed further in Section 2.1.2.1.

2.1.2.1.  SignerInfo

   The firmware package signer is represented in the SignerInfo type.
   The fields of SignerInfo are used as follows:

   version is the syntax version number, and it MUST be 3.

   sid identifies the signer's public key.  CMS supports two
      alternatives: issuerAndSerialNumber and subjectKeyIdentifier.
      However, the bootstrap loader MUST support the
      subjectKeyIdentifier alternative, which identifies the signer's
      public key directly.  When this public key is contained in a
      certificate, this identifier SHOULD appear in the X.509
      subjectKeyIdentifier extension.

   digestAlgorithm identifies the message digest algorithm, and any
      associated parameters, used by the firmware package signer.  It
      MUST contain the message digest algorithms employed by the
      firmware package signer.  (Note that this message digest algorithm
      identifier MUST be the same as the one carried in the
      digestAlgorithms value in SignedData.)

   signedAttrs is an optional collection of attributes that are signed
      along with the content.  The signedAttrs are optional in the CMS,
      but in this specification, signedAttrs are REQUIRED for the
      firmware package; however, implementations MUST ignore
      unrecognized signed attributes.  The SET OF attributes MUST be DER





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      encoded [X.509-88].  Section 2.2 of this document lists the
      attributes that MUST be included in the collection; other
      attributes MAY be included as well.

   signatureAlgorithm identifies the signature algorithm, and any
      associated parameters, used by the firmware package signer to
      generate the digital signature.

   signature is the digital signature value.

   unsignedAttrs is an optional SET of attributes that are not signed.
      As described in Section 2.3, this set can only contain a single
      instance of the wrapped-firmware-decryption-key attribute and no
      others.

2.1.2.2.  EncapsulatedContentInfo

   The EncapsulatedContentInfo content type encapsulates the firmware
   package, which might be compressed, encrypted, or compressed and then
   encrypted prior to signature.  The firmware package, in any of these
   formats, is carried within the EncapsulatedContentInfo type.  The
   fields of EncapsulatedContentInfo are used as follows:

   eContentType is an object identifier that uniquely specifies the
      content type, and in this case, the value MUST be id-encryptedData
      (1.2.840.113549.1.7.6), id-ct-compressedData
      (1.2.840.113549.1.9.16.1.9), or id-ct-firmwarePackage
      (1.2.840.113549.1.9.16.1.16).  When eContentType contains id-
      encryptedData, the firmware package was encrypted prior to
      signing, and may also have been compressed prior to encryption.
      When it contains id-ct-compressedData, the firmware package was
      compressed prior to signing, but was not encrypted.  When it
      contains id-ct-firmwarePackage, the firmware package was not
      compressed or encrypted prior to signing.

   eContent contains the signed firmware package, which might also be
      encrypted, compressed, or compressed and then encrypted, prior to
      signing.  The content is encoded as an octet string.  The eContent
      octet string need not be DER encoded.

2.1.3.  EncryptedData

   The EncryptedData content type [CMS] contains the encrypted firmware
   package (which might be compressed prior to encryption).  However, if
   the firmware package was not encrypted, the EncryptedData content
   type is not present.  The fields of EncryptedData are used as
   follows:




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   version is the syntax version number, and in this case, version MUST
      be 0.

   encryptedContentInfo is the encrypted content information.  The use
      of the EncryptedContentInfo type is discussed further in Section
      2.1.3.1.

   unprotectedAttrs is an optional collection of unencrypted attributes,
      and in this case, unprotectedAttrs MUST NOT be present.

2.1.3.1.  EncryptedContentInfo

   The encrypted firmware package, which might be compressed prior to
   encryption, is encapsulated in the EncryptedContentInfo type.  The
   fields of EncryptedContentInfo are used as follows:

   contentType indicates the type of content, and in this case, it MUST
      contain either id-ct-compressedData (1.2.840.113549.1.9.16.1.9) or
      id-ct-firmwarePackage (1.2.840.113549.1.9.16.1.16).  When it
      contains id-ct-compressedData, then the firmware package was
      compressed prior to encryption.  When it contains id-ct-
      firmwarePackage, then the firmware package was not compressed
      prior to encryption.

   contentEncryptionAlgorithm identifies the firmware-encryption
      algorithm, and any associated parameters, used to encrypt the
      firmware package.

   encryptedContent is the result of encrypting the firmware package.
      The field is optional; however, in this case, it MUST be present.

2.1.4.  CompressedData

   The CompressedData content type [COMPRESS] contains the compressed
   firmware package.  If the firmware package was not compressed, then
   the CompressedData content type is not present.  The fields of
   CompressedData are used as follows:

   version is the syntax version number; in this case, it MUST be 0.

   compressionAlgorithm identifies the compression algorithm, and any
      associated parameters, used to compress the firmware package.

   encapContentInfo is the compressed content, consisting of a content
      type identifier and the content itself.  The use of the
      EncapsulatedContentInfo type is discussed further in Section
      2.1.4.1.




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2.1.4.1.  EncapsulatedContentInfo

   The CompressedData content type encapsulates the compressed firmware
   package, and it is carried within the EncapsulatedContentInfo type.
   The fields of EncapsulatedContentInfo are used as follows:

   eContentType is an object identifier that uniquely specifies the
      content type, and in this case, it MUST be the value of id-ct-
      firmwarePackage (1.2.840.113549.1.9.16.1.16).

   eContent is the compressed firmware package, encoded as an octet
      string.  The eContent octet string need not be DER encoded.

2.1.5.  FirmwarePkgData

   The FirmwarePkgData content type contains the firmware package.  It
   is a straightforward encapsulation in an octet string, and it need
   not be DER encoded.

   The FirmwarePkgData content type is identified by the id-ct-
   firmwarePackage object identifier:

      id-ct-firmwarePackage OBJECT IDENTIFIER ::= {
        iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
        smime(16) ct(1) 16 }

   The FirmwarePkgData content type is a simple octet string:

      FirmwarePkgData ::= OCTET STRING

2.2.  Signed Attributes

   The firmware package signer MUST digitally sign a collection of
   attributes along with the firmware package.  Each attribute in the
   collection MUST be DER encoded [X.509-88].  The syntax for attributes
   is defined in [CMS], but it is repeated here for convenience:

      Attribute ::= SEQUENCE {
        attrType OBJECT IDENTIFIER,
        attrValues SET OF AttributeValue }

      AttributeValue ::= ANY

   Each of the attributes used with this profile has a single attribute
   value, even though the syntax is defined as a SET OF AttributeValue.
   There MUST be exactly one instance of AttributeValue present.





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   The SignedAttributes syntax within signerInfo is defined as a SET OF
   Attribute.  The SignedAttributes MUST include only one instance of
   any particular attribute.

   The firmware package signer MUST include the following four
   attributes: content-type, message-digest, firmware-package-
   identifier, and target-hardware-module-identifiers.

   If the firmware package is encrypted, then the firmware package
   signer MUST also include the decrypt-key-identifier attribute.

   If the firmware package implements cryptographic algorithms, then the
   firmware package signer MAY also include the implemented-crypto-
   algorithms attribute.  Similarly, if the firmware package implements
   compression algorithms, then the firmware package signer MAY also
   include the implemented-compress-algorithms attribute.

   If the firmware package is intended for use only by specific
   communities, then the firmware package signer MUST also include the
   community-identifiers attribute.

   If the firmware package depends on the presence of one or more other
   firmware packages to operate properly, then the firmware package
   signer SHOULD also include the firmware-package-info attribute.  For
   example, the firmware-package-info attribute dependencies field might
   indicate that the firmware package contains a dependency on a
   particular bootstrap loader or separation kernel.

   The firmware package signer SHOULD also include the three following
   attributes: firmware-package-message-digest, signing-time, and
   content-hints.  Additionally, if the firmware package signer has a
   certificate (meaning that the firmware package signer is not always
   configured as a trust anchor), then the firmware package signer
   SHOULD also include the signing-certificate attribute.

   The firmware package signer MAY include any other attribute that it
   deems appropriate.

2.2.1.  Content Type

   The firmware package signer MUST include a content-type attribute
   with the value of id-encryptedData (1.2.840.113549.1.7.6), id-ct-
   compressedData (1.2.840.113549.1.9.16.1.9), or id-ct-firmwarePackage
   (1.2.840.113549.1.9.16.1.16).  When it contains id-encryptedData, the
   firmware package was encrypted prior to signing.  When it contains
   id-ct-compressedData, the firmware package was compressed prior to
   signing, but was not encrypted.  When it contains




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   id-ct-firmwarePackage, the firmware package was not compressed or
   encrypted prior to signing.  Section 11.1 of [CMS] defines the
   content-type attribute.

2.2.2.  Message Digest

   The firmware package signer MUST include a message-digest attribute,
   having as its value the message digest computed on the
   encapContentInfo eContent octet string, as defined in Section
   2.1.2.2.  This octet string contains the firmware package, and it MAY
   be compressed, encrypted, or both compressed and encrypted.  Section
   11.2 of [CMS] defines the message-digest attribute.

2.2.3.  Firmware Package Identifier

   The firmware-package-identifier attribute names the protected
   firmware package.  Two approaches to naming firmware packages are
   supported:  legacy and preferred.  The firmware package signer MUST
   include a firmware-package-identifier attribute using one of these
   name forms.

   A legacy firmware package name is an octet string, and no structure
   within the octet string is assumed.

   A preferred firmware package name is a combination of an object
   identifier and a version number.  The object identifier names a
   collection of functions implemented by the firmware package, and the
   version number is a non-negative integer that identifies a particular
   build or release of the firmware package.

   If a firmware package with a disastrous flaw is released, the
   firmware package that repairs the previously distributed flaw MAY
   designate a stale firmware package version to prevent the reloading
   of the flawed version.  The hardware module bootstrap loader SHOULD
   prevent subsequent rollback to the stale version or versions earlier
   than the stale version.  When the legacy firmware package name form
   is used, the stale version is indicated by a stale legacy firmware
   package name, which is an octet string.  We assume that the firmware
   package signer and the bootstrap loader can determine whether a given
   legacy firmware package name represents a version that is more recent
   than the stale one.  When the preferred firmware package name form is
   used, the stale version is indicated by a stale version number, which
   is an integer.








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   The following object identifier identifies the firmware-package-
   identifier attribute:

      id-aa-firmwarePackageID OBJECT IDENTIFIER ::= {
        iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
        smime(16) aa(2) 35 }

   The firmware-package-identifier attribute values have ASN.1 type
   FirmwarePackageIdentifier:

      FirmwarePackageIdentifier ::= SEQUENCE {
        name PreferredOrLegacyPackageIdentifier,
        stale PreferredOrLegacyStalePackageIdentifier OPTIONAL }

      PreferredOrLegacyPackageIdentifier ::= CHOICE {
        preferred PreferredPackageIdentifier,
        legacy OCTET STRING }

      PreferredPackageIdentifier ::= SEQUENCE {
        fwPkgID OBJECT IDENTIFIER,
        verNum INTEGER (0..MAX) }

      PreferredOrLegacyStalePackageIdentifier ::= CHOICE {
        preferredStaleVerNum INTEGER (0..MAX),
        legacyStaleVersion OCTET STRING }

2.2.4.  Target Hardware Module Identifiers

   The target-hardware-module-identifiers attribute names the types of
   hardware modules that the firmware package supports.  A unique object
   identifier names each supported hardware model type and revision.

   The bootstrap loader MUST reject the firmware package if its own
   hardware module type identifier is not listed in the target-
   hardware-module-identifiers attribute.

   The following object identifier identifies the target-hardware-
   module-identifiers attribute:

      id-aa-targetHardwareIDs OBJECT IDENTIFIER ::= {
        iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
        smime(16) aa(2) 36 }

   The target-hardware-module-identifiers attribute values have ASN.1
   type TargetHardwareIdentifiers:

      TargetHardwareIdentifiers ::= SEQUENCE OF OBJECT IDENTIFIER




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2.2.5.  Decrypt Key Identifier

   The decrypt-key-identifier attribute names the symmetric key needed
   to decrypt the encapsulated firmware package.  The CMS EncryptedData
   content type is used when the firmware package is encrypted.  The
   decrypt-key-identifier signed attribute is carried in the SignedData
   content type that encapsulates EncryptedData content type, naming the
   symmetric key needed to decrypt the firmware package.  No particular
   structure is imposed on the key identifier.  The means by which the
   firmware-decryption key is securely distributed to all modules that
   are authorized to use the associated firmware package is beyond the
   scope of this specification; however, an optional mechanism for
   securely distributing the firmware-decryption key with the firmware
   package is specified in Section 2.3.1.

   The following object identifier identifies the decrypt-key-identifier
   attribute:

      id-aa-decryptKeyID OBJECT IDENTIFIER ::= {
        iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
        smime(16) aa(2) 37 }

   The decrypt-key-identifier attribute values have ASN.1 type
   DecryptKeyIdentifier:

      DecryptKeyIdentifier ::= OCTET STRING

2.2.6.  Implemented Crypto Algorithms

   The implemented-crypto-algorithms attribute MAY be present in the
   SignedAttributes, and it names the cryptographic algorithms that are
   implemented by the firmware package and available to applications.
   Only those algorithms that are made available at the interface of the
   cryptographic module are listed.  Any cryptographic algorithm that is
   used internally and is not accessible via the cryptographic module
   interface MUST NOT be listed.  For example, if the firmware package
   implements the decryption algorithm for future firmware package
   installations and this algorithm is not made available for other
   uses, then the firmware-decryption algorithm would not be listed.

   The object identifier portion of AlgorithmIdentifier identifies an
   algorithm and its mode of use.  No algorithm parameters are included.
   Cryptographic algorithms include traffic-encryption algorithms, key-
   encryption algorithms, key transport algorithms, key agreement
   algorithms, one-way hash algorithms, and digital signature
   algorithms.  Cryptographic algorithms do not include compression
   algorithms.




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   The following object identifier identifies the implemented-crypto-
   algorithms attribute:

      id-aa-implCryptoAlgs OBJECT IDENTIFIER ::= {
        iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
        smime(16) aa(2) 38 }

   The implemented-crypto-algorithms attribute values have ASN.1 type
   ImplementedCryptoAlgorithms:

      ImplementedCryptoAlgorithms ::= SEQUENCE OF OBJECT IDENTIFIER

2.2.7.  Implemented Compression Algorithms

   The implemented-compress-algorithms attribute MAY be present in the
   SignedAttributes, and it names the compression algorithms that are
   implemented by the firmware package and available to applications.
   Only those algorithms that are made available at the interface of the
   hardware module are listed.  Any compression algorithm that is used
   internally and is not accessible via the hardware module interface
   MUST NOT be listed.  For example, if the firmware package implements
   a decompression algorithm for future firmware package installations
   and this algorithm is not made available for other uses, then the
   firmware-decompression algorithm would not be listed.

   The object identifier portion of AlgorithmIdentifier identifies a
   compression algorithm.  No algorithm parameters are included.

   The following object identifier identifies the implemented-compress-
   algorithms attribute:

      id-aa-implCompressAlgs OBJECT IDENTIFIER ::= {
        iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
        smime(16) aa(2) 43 }

   The implemented-compress-algorithms attribute values have ASN.1 type
   ImplementedCompressAlgorithms:

      ImplementedCompressAlgorithms ::= SEQUENCE OF OBJECT IDENTIFIER

2.2.8.  Community Identifiers

   If present in the SignedAttributes, the community-identifiers
   attribute names the communities that are permitted to execute the
   firmware package.  The bootstrap loader MUST reject the firmware
   package if the hardware module is not a member of one of the
   identified communities.  The means of assigning community membership
   is beyond the scope of this specification.



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   The community-identifiers attributes names the authorized communities
   by a list of community object identifiers, by a list of specific
   hardware modules, or by a combination of the two lists.  A specific
   hardware module is specified by the combination of the hardware
   module identifier (as defined in Section 2.2.4) and a serial number.
   To facilitate compact representation of serial numbers, a contiguous
   block can be specified by the lowest authorized serial number and the
   highest authorized serial number.  Alternatively, all of the serial
   numbers associated with a hardware module family identifier can be
   specified with the NULL value.

   If the bootstrap loader does not have a mechanism for obtaining a
   list of object identifiers that identify the communities to which the
   hardware module is a member, then the bootstrap loader MUST behave as
   though the list is empty.  Similarly, if the bootstrap loader does
   not have access to the hardware module serial number, then the
   bootstrap loader MUST behave as though the hardware module is not
   included on the list of authorized hardware modules.

   The following object identifier identifies the community-identifiers
   attribute:

      id-aa-communityIdentifiers OBJECT IDENTIFIER ::= {
        iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
        smime(16) aa(2) 40 }

   The community-identifiers attribute values have ASN.1 type
   CommunityIdentifiers:

      CommunityIdentifiers ::= SEQUENCE OF CommunityIdentifier

      CommunityIdentifier ::= CHOICE {
        communityOID OBJECT IDENTIFIER,
        hwModuleList HardwareModules }

      HardwareModules ::= SEQUENCE {
        hwType OBJECT IDENTIFIER,
        hwSerialEntries SEQUENCE OF HardwareSerialEntry }

      HardwareSerialEntry ::= CHOICE {
        all NULL,
        single OCTET STRING,
        block SEQUENCE {
          low OCTET STRING,
          high OCTET STRING } }






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2.2.9.  Firmware Package Information

   If a hardware module supports more than one type of firmware package,
   then the firmware package signer SHOULD include the firmware-
   package-info attribute with a populated fwPkgType field to identify
   the firmware package type.  This value can aid the bootstrap loader
   in the correct placement of the firmware package within the hardware
   module.  The firmware package type is an INTEGER, and the meaning of
   the integer value is specific to each hardware module.  For example,
   a hardware module could assign different integer values for a
   bootstrap loader, a separation kernel, and an application.

   Some hardware module architectures permit one firmware package to use
   routines provided by another.  If the firmware package contains a
   dependency on another, then the firmware package signer SHOULD also
   include the firmware-package-info attribute with a populated
   dependencies field.  If the firmware package does not depend on any
   other firmware packages, then the firmware package signer MUST NOT
   include the firmware-package-info attribute with a populated
   dependencies field.

   Firmware package dependencies are identified by the firmware package
   identifier or by information contained in the firmware package
   itself, and in either case the bootstrap loader ensures that the
   dependencies are met.  The bootstrap loader MUST reject a firmware
   package load if it identifies a dependency on a firmware package that
   is not already loaded.  Also, the bootstrap loader MUST reject a
   firmware package load if the action will result in a configuration
   where the dependencies of an already loaded firmware package will no
   longer be satisfied.  As described in Section 2.2.3, two approaches
   to naming firmware packages are supported: legacy and preferred.
   When the legacy firmware package name form is used, the dependency is
   indicated by a legacy firmware package name.  We assume that the
   firmware package signer and the bootstrap loader can determine
   whether a given legacy firmware package name represents the named
   version of an acceptable newer version.  When the preferred firmware
   package name form is used, an object identifier and an integer are
   provided.  The object identifier MUST exactly match the object
   identifier portion of a preferred firmware package name associated
   with a firmware package that is already loaded, and the integer MUST
   be less than or equal to the integer portion of the preferred
   firmware package name associated with the same firmware package.
   That is, the dependency specifies the minimum value of the version
   that is acceptable.







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   The following object identifier identifies the firmware-package-info
   attribute:

      id-aa-firmwarePackageInfo OBJECT IDENTIFIER ::= {
        iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
        smime(16) aa(2) 42 }

   The firmware-package-info attribute values have ASN.1 type
   FirmwarePackageInfo:

      FirmwarePackageInfo ::= SEQUENCE {
        fwPkgType INTEGER OPTIONAL,
        dependencies SEQUENCE OF
          PreferredOrLegacyPackageIdentifier OPTIONAL }

2.2.10.  Firmware Package Message Digest

   The firmware package signer SHOULD include a firmware-package-
   message-digest attribute, which provides the message digest algorithm
   and the message digest value computed on the firmware package.  The
   message digest is computed on the firmware package prior to any
   compression, encryption, or signature processing.  The bootstrap
   loader MAY use this message digest to confirm that the intended
   firmware package has been recovered after all of the layers of
   encapsulation are removed.

   The following object identifier identifies the firmware-package-
   message-digest attribute:

      id-aa-fwPkgMessageDigest OBJECT IDENTIFIER ::= {
        iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
        smime(16) aa(2) 41 }

   The firmware-package-message-digest attribute values have ASN.1 type
   FirmwarePackageMessageDigest:

      FirmwarePackageMessageDigest ::= SEQUENCE {
        algorithm AlgorithmIdentifier,
        msgDigest OCTET STRING }

2.2.11.  Signing Time

   The firmware package signer SHOULD include a signing-time attribute,
   specifying the time at which the signature was applied to the
   firmware package.  Section 11.3 of [CMS] defines the signing-time
   attribute.





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2.2.12.  Content Hints

   The firmware package signer SHOULD include a content-hints attribute,
   including a brief text description of the firmware package.  The text
   is encoded in UTF-8, which supports most of the world's writing
   systems [UTF-8].  Section 2.9 of [ESS] defines the content-hints
   attribute.

   When multiple layers of encapsulation are employed, the content-hints
   attribute is included in the outermost SignedData to provide
   information about the innermost content.  In this case, the content-
   hints attribute provides a brief text description of the firmware
   package, which can help a person select the correct firmware package
   when more than one is available.

   When the preferred firmware package name forms are used, the
   content-hints attribute can provide a linkage to a legacy firmware
   package name.  This is especially helpful when an existing
   configuration management system is in use, but the features
   associated with the preferred firmware package name are deemed
   useful.  A firmware package name associated with such a configuration
   management system might look something like
   "R1234.C0(AJ11).D62.A02.11(b)."  Including these firmware package
   names in the text description may be helpful to developers by
   providing a clear linkage between the two name forms.

   The content-hints attribute contains two fields, and in this case,
   both fields MUST be present.  The fields of ContentHints are used as
   follows:

   contentDescription provides a brief text description of the firmware
      package.

   contentType provides the content type of the inner most content type,
      and in this case, it MUST be id-ct-firmwarePackage
      (1.2.840.113549.1.9.16.1.16).

2.2.13.  Signing Certificate

   When the firmware-signer's public key is contained in a certificate,
   the firmware package signer SHOULD include a signing-certificate
   attribute to identify the certificate that was employed.  However, if
   the firmware package signature does not have a certificate (meaning
   that the signature will only be validated with the trust anchor
   public key), then the firmware package signer is unable to include a
   signing-certificate attribute.  Section 5.4 of [ESS] defines this
   attribute.




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   The signing-certificate attribute contains two fields: certs and
   policies.  The certs field MUST be present, and the policies field
   MAY be present.  The fields of SigningCertificate are used as
   follows:

   certs contains a sequence of certificate identifiers.  In this case,
      sequence of certificate identifiers contains a single entry.  The
      certs field MUST contain only the certificate identifier of the
      certificate that contains the public key used to verify the
      firmware package signature.  The certs field uses the ESSCertID
      syntax specified in Section 5.4 of [ESS], and it is comprised of
      the SHA-1 hash [SHA1] of the entire ASN.1 DER encoded certificate
      and, optionally, the certificate issuer and the certificate serial
      number.  The SHA-1 hash value MUST be present.  The certificate
      issuer and the certificate serial number SHOULD be present.

   policies is optional; when it is present, it contains a sequence of
      policy information.  The policies field, when present, MUST
      contain only one entry, and that entry MUST match one of the
      certificate policies in the certificate policies extension of the
      certificate that contains the public key used to verify the
      firmware package signature.  The policies field uses the
      PolicyInformation syntax specified in Section 4.2.1.5 of
      [PROFILE], and it is comprised of the certificate policy object
      identifier and, optionally, certificate policy qualifiers.  The
      certificate policy object identifier MUST be present.  The
      certificate policy qualifiers SHOULD NOT be present.

2.3.  Unsigned Attributes

   CMS allows a SET of unsigned attributes to be included; however, in
   this specification, the set MUST be absent or include a single
   instance of the wrapped-firmware-decryption-key attribute.  Because
   the digital signature does not cover this attribute, it can be
   altered at any point in the delivery path from the firmware package
   signer to the hardware module.  This property can be employed to
   distribute the firmware-decryption key along with an encrypted and
   signed firmware package, allowing the firmware-decryption key to be
   wrapped with a different key-encryption key for each link in the
   distribution chain.

   The syntax for attributes is defined in [CMS], and it is repeated at
   the beginning of Section 2.2 of this document for convenience.  Each
   of the attributes used with this profile has a single attribute
   value, even though the syntax is defined as a SET OF AttributeValue.
   There MUST be exactly one instance of AttributeValue present.





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   The UnsignedAttributes syntax within signerInfo is defined as a SET
   OF Attribute.  The UnsignedAttributes MUST include only one instance
   of any particular attribute.

2.3.1.  Wrapped Firmware Decryption Key

   The firmware package signer, or any other party in the distribution
   chain, MAY include a wrapped-firmware-decryption-key attribute.

   The following object identifier identifies the wrapped-firmware-
   decryption-key attribute:

      id-aa-wrappedFirmwareKey OBJECT IDENTIFIER ::= {
        iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
        smime(16) aa(2) 39 }

   The wrapped-firmware-decryption-key attribute values have ASN.1 type
   of EnvelopedData.  Section 6 of [CMS] defines the EnvelopedData
   content type, which is used to construct the value of the attribute.
   EnvelopedData permits the firmware-decryption key to be protected
   using symmetric or asymmetric techniques.  The EnvelopedData does not
   include an encrypted content; rather, the EnvelopedData feature of
   having the encrypted content in another location is employed.  The
   encrypted content is found in the eContent field of the EncryptedData
   structure.  The firmware-decryption key is contained in the
   recipientInfos field.  Section 6 of [CMS] refers to this key as the
   content-encryption key.

   The EnvelopedData syntax supports many different key management
   algorithms.  Four general techniques are supported: key transport,
   key agreement, symmetric key-encryption keys, and passwords.

   The EnvelopedData content type is profiled for the wrapped-firmware-
   decryption-key attribute.  The EnvelopedData fields are described
   fully in Section 6 of [CMS].  Additional rules apply when
   EnvelopedData is used as a wrapped-firmware-decryption-key attribute.

   Within the EnvelopedData structure, the following apply:

   -  The set of certificates included in OriginatorInfo MUST NOT
      include certificates with a type of extendedCertificate,
      v1AttrCert, or v2AttrCert [X.509-97, X.509-00, ACPROFILE].  The
      optional crls field MAY be present.

   -  The optional unprotectedAttrs field MUST NOT be present.






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   Within the EncryptedContentInfo structure, the following apply:

   -  contentType MUST match the content type object identifier carried
      in the contentType field within the EncryptedContentInfo structure
      of EncryptedData as described in Section 2.1.3.1.

   -  contentEncryptionAlgorithm identifies the firmware-encryption
      algorithm, and any associated parameters, used to encrypt the
      firmware package carried in the encryptedContent field of the
      EncryptedContentInfo structure of EncryptedData.  Therefore, it
      MUST exactly match the value of the EncryptedContentInfo structure
      of EncryptedData as described in Section 2.1.3.1.

   -  encryptedContent is optional, and in this case, it MUST NOT be
      present.

3.  Firmware Package Load Receipt

   The Cryptographic Message Syntax (CMS) is used to indicate that a
   firmware package loaded successfully.  Support for firmware package
   load receipts is OPTIONAL.  However, those hardware modules that
   choose to generate such receipts MUST follow the conventions
   specified in this section.  Because not all hardware modules will
   have private signature keys, the firmware package load receipt can be
   either signed or unsigned.  Use of the signed firmware package load
   receipt is RECOMMENDED.

   Hardware modules that support receipt generation MUST have a unique
   serial number.  Hardware modules that support signed receipt
   generation MUST have a private signature key to sign the receipt and
   the corresponding signature validation certificate or its designator.
   The designator is the certificate issuer name and the certificate
   serial number, or it is the public key identifier.  Memory-
   constrained hardware modules will generally store the public key
   identifier since it requires less storage.

   The unsigned firmware package load receipt is encapsulated by
   ContentInfo.  Alternatively, the signed firmware package load receipt
   is encapsulated by SignedData, which is in turn encapsulated by
   ContentInfo.











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   The firmware package load receipt is summarized as follows (see [CMS]
   for the full syntax):

   ContentInfo {
     contentType          id-signedData, -- (1.2.840.113549.1.7.2)
                          -- OR --
                          id-ct-firmwareLoadReceipt,
                               -- (1.2.840.113549.1.9.16.1.17)
     content              SignedData
                          -- OR --
                          FirmwarePackageLoadReceipt
   }

   SignedData {
     version              CMSVersion, -- always set to 3
     digestAlgorithms     DigestAlgorithmIdentifiers, -- Only one
     encapContentInfo     EncapsulatedContentInfo,
     certificates         CertificateSet, -- Optional Module certificate
     crls                 CertificateRevocationLists, -- Optional
     signerInfos          SET OF SignerInfo -- Only one
   }

   SignerInfo {
     version              CMSVersion, -- either set to 1 or 3
     sid                  SignerIdentifier,
     digestAlgorithm      DigestAlgorithmIdentifier,
     signedAttrs          SignedAttributes, -- Required
     signatureAlgorithm   SignatureAlgorithmIdentifier,
     signature            SignatureValue,
     unsignedAttrs        UnsignedAttributes -- Omit
   }

   EncapsulatedContentInfo {
     eContentType         id-ct-firmwareLoadReceipt,
                               -- (1.2.840.113549.1.9.16.1.17)
     eContent             OCTET STRING -- Contains receipt
   }

   FirmwarePackageLoadReceipt {
     version              INTEGER, -- The DEFAULT is always used
     hwType               OBJECT IDENTIFIER, -- Hardware module type
     hwSerialNum          OCTET STRING, -- H/W module serial number
     fwPkgName            PreferredOrLegacyPackageIdentifier,
     trustAnchorKeyID     OCTET STRING, -- Optional
     decryptKeyID         OCTET STRING -- Optional
   }





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3.1.  Firmware Package Load Receipt CMS Content Type Profile

   This section specifies the conventions for using the CMS ContentInfo
   and SignedData content types for firmware package load receipts.  It
   also defines the firmware package load receipt content type.

3.1.1.  ContentInfo

   The CMS requires that the outermost encapsulation be ContentInfo
   [CMS].  The fields of ContentInfo are used as follows:

   contentType indicates the type of the associated content.  If the
      firmware package load receipt is signed, then the encapsulated
      type MUST be SignedData, and the id-signedData
      (1.2.840.113549.1.7.2) object identifier MUST be present in this
      field.  If the receipt is not signed, then the encapsulated type
      MUST be FirmwarePackageLoadReceipt, and the id-ct-
      firmwareLoadReceipt (1.2.840.113549.1.9.16.1.17) object identifier
      MUST be present in this field.

   content holds the associated content.  If the firmware package load
      receipt is signed, then this field MUST contain the SignedData.
      If the receipt is not signed, then this field MUST contain the
      FirmwarePackageLoadReceipt.

3.1.2.  SignedData

   The SignedData content type contains the firmware package load
   receipt and one digital signature.  If the hardware module locally
   stores its certificate, then the certificate can be included as well.
   The fields of SignedData are used as follows:

   version is the syntax version number, and in this case, it MUST be
      set to 3.

   digestAlgorithms is a collection of message digest algorithm
      identifiers, and in this case, it MUST contain a single message
      digest algorithm identifier.  The message digest algorithms
      employed by the hardware module MUST be present.

   encapContentInfo is the signed content, consisting of a content type
      identifier and the content itself.  The use of the
      EncapsulatedContentInfo type is discussed further in Section
      3.1.2.2.

   certificates is an optional collection of certificates.  If the
      hardware module locally stores its certificate, then the X.509
      certificate of the hardware module SHOULD be included.  If the



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      hardware module does not, then the certificates field is omitted.
      PKCS#6 extended certificates [PKCS#6] and attribute certificates
      (either version 1 or version 2) [X.509-97, X.509-00, ACPROFILE]
      MUST NOT be included in the set of certificates.

   crls is an optional collection of certificate revocation lists
      (CRLs).  CRLs MAY be included, but they will normally be omitted
      since hardware modules will not generally have access to the most
      recent CRL.  Signed receipt recipients SHOULD be able to handle
      the presence of the optional crls field.

   signerInfos is a collection of per-signer information, and in this
      case, the collection MUST contain exactly one SignerInfo.  The use
      of the SignerInfo type is discussed further in Section 3.1.2.1.

3.1.2.1.  SignerInfo

   The hardware module is represented in the SignerInfo type.  The
   fields of SignerInfo are used as follows:

   version is the syntax version number, and it MUST be either 1 or 3,
      depending on the method used to identify the hardware module's
      public key.  The use of the subjectKeyIdentifier is RECOMMENDED,
      which results in the use of version 3.

   sid specifies the hardware module's certificate (and thereby the
      hardware module's public key).  CMS supports two alternatives:
      issuerAndSerialNumber and subjectKeyIdentifier.  The hardware
      module MUST support one or both of the alternatives for receipt
      generation; however, the support of subjectKeyIdentifier is
      RECOMMENDED.  The issuerAndSerialNumber alternative identifies the
      hardware module's certificate by the issuer's distinguished name
      and the certificate serial number.  The identified certificate, in
      turn, contains the hardware module's public key.  The
      subjectKeyIdentifier alternative identifies the hardware module's
      public key directly.  When this public key is contained in a
      certificate, this identifier SHOULD appear in the X.509
      subjectKeyIdentifier extension.

   digestAlgorithm identifies the message digest algorithm, and any
      associated parameters, used by the hardware module.  It MUST
      contain the message digest algorithms employed to sign the
      receipt.  (Note that this message digest algorithm identifier MUST
      be the same as the one carried in the digestAlgorithms value in
      SignedData.)






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   signedAttrs is an optional collection of attributes that are signed
      along with the content.  The signedAttrs are optional in the CMS,
      but in this specification, signedAttrs are REQUIRED for use with
      the firmware package load receipt content.  The SET OF attributes
      MUST be DER encoded [X.509-88].  Section 3.2 of this document
      lists the attributes that MUST be included in the collection.
      Other attributes MAY be included, but the recipient will ignore
      any unrecognized signed attributes.

   signatureAlgorithm identifies the signature algorithm, and any
      associated parameters, used to sign the receipt.

   signature is the digital signature.

   unsignedAttrs is an optional collection of attributes that are not
      signed, and in this case, there MUST NOT be any unsigned
      attributes present.

3.1.2.2.  EncapsulatedContentInfo

   The FirmwarePackageLoadReceipt is encapsulated in an OCTET STRING,
   and it is carried within the EncapsulatedContentInfo type.  The
   fields of EncapsulatedContentInfo are used as follows:

   eContentType is an object identifier that uniquely specifies the
      content type, and in this case, it MUST be the value of id-ct-
      firmwareLoadReceipt (1.2.840.113549.1.9.16.1.17).

   eContent is the firmware package load receipt, encapsulated in an
      OCTET STRING.  The eContent octet string need not be DER encoded.

3.1.3.  FirmwarePackageLoadReceipt

   The following object identifier identifies the firmware package load
   receipt content type:

      id-ct-firmwareLoadReceipt OBJECT IDENTIFIER ::= {
        iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
        smime(16) ct(1) 17 }












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   The firmware package load receipt content type has the ASN.1 type
   FirmwarePackageLoadReceipt:

      FirmwarePackageLoadReceipt ::= SEQUENCE {
        version FWReceiptVersion DEFAULT v1,
        hwType OBJECT IDENTIFIER,
        hwSerialNum OCTET STRING,
        fwPkgName PreferredOrLegacyPackageIdentifier,
        trustAnchorKeyID OCTET STRING OPTIONAL,
        decryptKeyID [1] OCTET STRING OPTIONAL }

      FWReceiptVersion ::= INTEGER { v1(1) }

   The fields of the FirmwarePackageLoadReceipt type have the following
   meanings:

   version is an integer that provides the syntax version number for
      compatibility with future revisions of this specification.
      Implementations that conform to this specification MUST set the
      version to the default value, which is v1.

   hwType is an object identifier that identifies the type of hardware
      module on which the firmware package was loaded.

   hwSerialNum is the serial number of the hardware module on which the
      firmware package was loaded.  No particular structure is imposed
      on the serial number; it need not be an integer.  However, the
      combination of the hwType and hwSerialNum uniquely identifies the
      hardware module.

   fwPkgName identifies the firmware package that was loaded.  As
      described in Section 2.2.3, two approaches to naming firmware
      packages are supported: legacy and preferred.  A legacy firmware
      package name is an octet string.  A preferred firmware package
      name is a combination of the firmware package object identifier
      and an integer version number.

   trustAnchorKeyID is optional, and when it is present, it identifies
      the trust anchor that was used to validate the firmware package
      signature.

   decryptKeyID is optional, and when it is present, it identifies the
      firmware-decryption key that was used to decrypt the firmware
      package.

   The firmware package load receipt MUST include the version, hwType,
   hwSerialNum, and fwPkgName fields, and it SHOULD include the
   trustAnchorKeyID field.  The firmware package load receipt MUST NOT



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   include the decryptKeyID, unless the firmware package associated with
   the receipt is encrypted, the firmware-decryption key is available to
   the hardware module, and the firmware package was successfully
   decrypted.

3.2.  Signed Attributes

   The hardware module MUST digitally sign a collection of attributes
   along with the firmware package load receipt.  Each attribute in the
   collection MUST be DER encoded [X.509-88].  The syntax for attributes
   is defined in [CMS], and it was repeated in Section 2.2 for
   convenience.

   Each of the attributes used with this profile has a single attribute
   value, even though the syntax is defined as a SET OF AttributeValue.
   There MUST be exactly one instance of AttributeValue present.

   The SignedAttributes syntax within signerInfo is defined as a SET OF
   Attributes.  The SignedAttributes MUST include only one instance of
   any particular attribute.

   The hardware module MUST include the content-type and message-digest
   attributes.  If the hardware module includes a real-time clock, then
   the hardware module SHOULD also include the signing-time attribute.
   The hardware module MAY include any other attribute that it deems
   appropriate.

3.2.1.  Content Type

   The hardware module MUST include a content-type attribute with the
   value of id-ct-firmwareLoadReceipt (1.2.840.113549.1.9.16.1.17).
   Section 11.1 of [CMS] defines the content-type attribute.

3.2.2.  Message Digest

   The hardware module MUST include a message-digest attribute, having
   as its value the message digest of the FirmwarePackageLoadReceipt
   content.  Section 11.2 of [CMS] defines the message-digest attribute.

3.2.3.  Signing Time

   If the hardware module includes a real-time clock, then the hardware
   module SHOULD include a signing-time attribute, specifying the time
   at which the receipt was generated.  Section 11.3 of [CMS] defines
   the signing-time attribute.






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4.  Firmware Package Load Error

   The Cryptographic Message Syntax (CMS) is used to indicate that an
   error has occurred while attempting to load a protected firmware
   package.  Support for firmware package load error reports is
   OPTIONAL.  However, those hardware modules that choose to generate
   such error reports MUST follow the conventions specified in this
   section.  Not all hardware modules have private signature keys;
   therefore the firmware package load error report can be either signed
   or unsigned.  Use of the signed firmware package error report is
   RECOMMENDED.

   Hardware modules that support error report generation MUST have a
   unique serial number.  Hardware modules that support signed error
   report generation MUST also have a private signature key to sign the
   error report and the corresponding signature validation certificate
   or its designator.  The designator is the certificate issuer name and
   the certificate serial number, or it is the public key identifier.
   Memory-constrained hardware modules will generally store the public
   key identifier since it requires less storage.

   The unsigned firmware package load error report is encapsulated by
   ContentInfo.  Alternatively, the signed firmware package load error
   report is encapsulated by SignedData, which is in turn encapsulated
   by ContentInfo.

   The firmware package load error report is summarized as follows (see
   [CMS] for the full syntax):

   ContentInfo {
     contentType          id-signedData, -- (1.2.840.113549.1.7.2)
                          -- OR --
                          id-ct-firmwareLoadError,
                               -- (1.2.840.113549.1.9.16.1.18)
     content              SignedData
                          -- OR --
                          FirmwarePackageLoadError
   }

   SignedData {
     version              CMSVersion, -- Always set to 3
     digestAlgorithms     DigestAlgorithmIdentifiers, -- Only one
     encapContentInfo     EncapsulatedContentInfo,
     certificates         CertificateSet, -- Optional Module certificate
     crls                 CertificateRevocationLists, -- Optional
     signerInfos          SET OF SignerInfo -- Only one
   }




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   SignerInfo {
     version              CMSVersion, -- either set to 1 or 3
     sid                  SignerIdentifier,
     digestAlgorithm      DigestAlgorithmIdentifier,
     signedAttrs          SignedAttributes, -- Required
     signatureAlgorithm   SignatureAlgorithmIdentifier,
     signature            SignatureValue,
     unsignedAttrs        UnsignedAttributes -- Omit
   }

   EncapsulatedContentInfo {
     eContentType         id-ct-firmwareLoadError,
                               -- (1.2.840.113549.1.9.16.1.18)
     eContent             OCTET STRING -- Contains error report
   }

   FirmwarePackageLoadError {
     version            INTEGER, -- The DEFAULT is always used
     hwType             OBJECT IDENTIFIER, -- Hardware module type
     hwSerialNum        OCTET STRING, -- H/W module serial number
     errorCode          FirmwarePackageLoadErrorCode -- Error identifier
     vendorErrorCode    VendorErrorCode, -- Optional
     fwPkgName          PreferredOrLegacyPackageIdentifier, -- Optional
     config             SEQUENCE OF CurrentFWConfig, -- Optional
   }

   CurrentFWConfig {      -- Repeated for each package in configuration
     fwPkgType            INTEGER, -- Firmware package type; Optional
     fwPkgName            PreferredOrLegacyPackageIdentifier
   }

4.1.  Firmware Package Load Error CMS Content Type Profile

   This section specifies the conventions for using the CMS ContentInfo
   and SignedData content types for firmware package load error reports.
   It also defines the firmware package load error content type.

4.1.1.  ContentInfo

   The CMS requires that the outermost encapsulation be ContentInfo
   [CMS].  The fields of ContentInfo are used as follows:

   contentType indicates the type of the associated content.  If the
      firmware package load error report is signed, then the
      encapsulated type MUST be SignedData, and the id-signedData
      (1.2.840.113549.1.7.2) object identifier MUST be present in this
      field.  If the report is not signed, then the encapsulated type




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      MUST be FirmwarePackageLoadError, and the id-ct-firmwareLoadError
      (1.2.840.113549.1.9.16.1.18) object identifier MUST be present in
      this field.

   content holds the associated content.  If the firmware package load
      error report is signed, then this field MUST contain the
      SignedData.  If the report is not signed, then this field MUST
      contain the FirmwarePackageLoadError.

4.1.2.  SignedData

   The SignedData content type contains the firmware package load error
   report and one digital signature.  If the hardware module locally
   stores its certificate, then the certificate can be included as well.
   The fields of SignedData are used exactly as described in Section
   3.1.2.

4.1.2.1.  SignerInfo

   The hardware module is represented in the SignerInfo type.  The
   fields of SignerInfo are used exactly as described in Section
   3.1.2.1.

4.1.2.2.  EncapsulatedContentInfo

   The FirmwarePackageLoadError is encapsulated in an OCTET STRING, and
   it is carried within the EncapsulatedContentInfo type.  The fields of
   EncapsulatedContentInfo are used as follows:

   eContentType is an object identifier that uniquely specifies the
      content type, and in this case, it MUST be the value of id-ct-
      firmwareLoadError (1.2.840.113549.1.9.16.1.18).

   eContent is the firmware package load error report, encapsulated in
      an OCTET STRING.  The eContent octet string need not be DER
      encoded.

4.1.3.  FirmwarePackageLoadError

   The following object identifier identifies the firmware package load
   error report content type:

      id-ct-firmwareLoadError OBJECT IDENTIFIER ::= {
        iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
        smime(16) ct(1) 18 }






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   The firmware package load error report content type has the ASN.1
   type FirmwarePackageLoadError:

      FirmwarePackageLoadError ::= SEQUENCE {
        version FWErrorVersion DEFAULT v1,
        hwType OBJECT IDENTIFIER,
        hwSerialNum OCTET STRING,
        errorCode FirmwarePackageLoadErrorCode,
        vendorErrorCode VendorLoadErrorCode OPTIONAL,
        fwPkgName PreferredOrLegacyPackageIdentifier OPTIONAL,
        config [1] SEQUENCE OF CurrentFWConfig OPTIONAL }

      FWErrorVersion ::= INTEGER { v1(1) }

      CurrentFWConfig ::= SEQUENCE {
        fwPkgType INTEGER OPTIONAL,
        fwPkgName PreferredOrLegacyPackageIdentifier }

      FirmwarePackageLoadErrorCode ::= ENUMERATED {
        decodeFailure                (1),
        badContentInfo               (2),
        badSignedData                (3),
        badEncapContent              (4),
        badCertificate               (5),
        badSignerInfo                (6),
        badSignedAttrs               (7),
        badUnsignedAttrs             (8),
        missingContent               (9),
        noTrustAnchor               (10),
        notAuthorized               (11),
        badDigestAlgorithm          (12),
        badSignatureAlgorithm       (13),
        unsupportedKeySize          (14),
        signatureFailure            (15),
        contentTypeMismatch         (16),
        badEncryptedData            (17),
        unprotectedAttrsPresent     (18),
        badEncryptContent           (19),
        badEncryptAlgorithm         (20),
        missingCiphertext           (21),
        noDecryptKey                (22),
        decryptFailure              (23),
        badCompressAlgorithm        (24),
        missingCompressedContent    (25),
        decompressFailure           (26),
        wrongHardware               (27),
        stalePackage                (28),
        notInCommunity              (29),



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        unsupportedPackageType      (30),
        missingDependency           (31),
        wrongDependencyVersion      (32),
        insufficientMemory          (33),
        badFirmware                 (34),
        unsupportedParameters       (35),
        breaksDependency            (36),
        otherError                  (99) }

      VendorLoadErrorCode ::= INTEGER

   The fields of the FirmwarePackageLoadError type have the following
   meanings:

   version is an integer, and it provides the syntax version number for
      compatibility with future revisions of this specification.
      Implementations that conform to this specification MUST set the
      version to the default value, which is v1.

   hwType is an object identifier that identifies the type of hardware
      module on which the firmware package load was attempted.

   hwSerialNum is the serial number of the hardware module on which the
      firmware package load was attempted.  No particular structure is
      imposed on the serial number; it need not be an integer.  However,
      the combination of the hwType and hwSerialNum uniquely identifies
      the hardware module.

   errorCode identifies the error that occurred.

   vendorErrorCode is optional; however, it MUST be present if the
      errorCode contains a value of otherError.  When errorCode contains
      a value other than otherError, the vendorErrorCode can provide
      vendor-specific supplemental information.

   fwPkgName is optional.  When it is present, it identifies the
      firmware package that was being loaded when the error occurred.
      As described in Section 2.2.3, two approaches to naming firmware
      packages are supported: legacy and preferred.  A legacy firmware
      package name is an octet string.  A preferred firmware package
      name is a combination of the firmware package object identifier
      and an integer version number.

   config identifies the current firmware configuration.  The field is
      OPTIONAL, but support for this field is RECOMMENDED for hardware
      modules that permit the loading of more than one firmware package.
      One instance of CurrentFWConfig is used to provide information
      about each firmware package in hardware module.



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   The fields of the CurrentFWConfig type have the following meanings:

   fwPkgType identifies the firmware package type.  The firmware package
      type is an INTEGER, and the meaning of the integer value is
      specific to each hardware module.

   fwPkgName identifies the firmware package.  As described in Section
      2.2.3, two approaches to naming firmware packages are supported:
      legacy and preferred.  A legacy firmware package name is an octet
      string.  A preferred firmware package name is a combination of the
      firmware package object identifier and an integer version number.

   The errorCode values have the following meanings:

   decodeFailure: The ASN.1 decode of the firmware package load failed.
      The provided input did not conform to BER, or it was not ASN.1 at
      all.

   badContentInfo: Invalid ContentInfo syntax, or the contentType
      carried within the ContentInfo is unknown or unsupported.

   badSignedData: Invalid SignedData syntax, the version is unknown or
      unsupported, or more than one entry is present in
      digestAlgorithms.

   badEncapContent: Invalid EncapsulatedContentInfo syntax, or the
      contentType carried within the eContentType is unknown or
      unsupported.  This error can be generated due to problems located
      in SignedData or CompressedData.

   badCertificate: Invalid syntax for one or more certificates in
      CertificateSet.

   badSignerInfo: Invalid SignerInfo syntax, or the version is unknown
      or unsupported.

   badSignedAttrs: Invalid signedAttrs syntax within SignerInfo.

   badUnsignedAttrs: The unsignedAttrs within SignerInfo contains an
      attribute other than the wrapped-firmware-decryption-key
      attribute, which is the only unsigned attribute supported by this
      specification.

   missingContent: The optional eContent is missing in
      EncapsulatedContentInfo, which is required in this specification.
      This error can be generated due to problems located in SignedData
      or CompressedData.




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   noTrustAnchor: Two situations can lead to this error.  In one case,
      the subjectKeyIdentifier does not identify the public key of a
      trust anchor or a certification path that terminates with an
      installed trust anchor.  In the other case, the
      issuerAndSerialNumber does not identify the public key of a trust
      anchor or a certification path that terminates with an installed
      trust anchor.

   notAuthorized: The sid within SignerInfo leads to an installed trust
      anchor, but that trust anchor is not an authorized firmware
      package signer.

   badDigestAlgorithm: The digestAlgorithm in either SignerInfo or
      SignedData is unknown or unsupported.

   badSignatureAlgorithm: The signatureAlgorithm in SignerInfo is
      unknown or unsupported.

   unsupportedKeySize: The signatureAlgorithm in SignerInfo is known and
      supported, but the firmware package signature could not be
      validated because an unsupported key size was employed by the
      signer.

   signatureFailure: The signatureAlgorithm in SignerInfo is known and
      supported, but the signature in signature in SignerInfo could not
      be validated.

   contentTypeMismatch: The contentType carried within the eContentType
      does not match the content type carried in the signed attribute.

   badEncryptedData: Invalid EncryptedData syntax; the version is
      unknown or unsupported.

   unprotectedAttrsPresent: EncryptedData contains unprotectedAttrs,
      which are not permitted in this specification.

   badEncryptContent: Invalid EncryptedContentInfo syntax, or the
      contentType carried within the contentType is unknown or
      unsupported.

   badEncryptAlgorithm: The firmware-encryption algorithm identified by
      contentEncryptionAlgorithm in EncryptedContentInfo is unknown or
      unsupported.

   missingCiphertext: The optional encryptedContent is missing in
      EncryptedContentInfo, which is required in this specification.





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   noDecryptKey: The hardware module does not have the firmware-
      decryption key named in the decrypt key identifier signed
      attribute.

   decryptFailure: The firmware package did not decrypt properly.

   badCompressAlgorithm: The compression algorithm identified by
      compressionAlgorithm in CompressedData is unknown or unsupported.

   missingCompressedContent: The optional eContent is missing in
      EncapsulatedContentInfo, which is required in this specification.

   decompressFailure: The firmware package did not decompress properly.

   wrongHardware: The processing hardware module is not listed in the
      target hardware module identifiers signed attribute.

   stalePackage: The firmware package is rejected because it is stale.

   notInCommunity: The hardware module is not a member of the community
      described in the community identifiers signed attribute.

   unsupportedPackageType: The firmware package type identified in the
      firmware package information signed attribute is not supported by
      the combination of the hardware module and the bootstrap loader.

   missingDependency: The firmware package being loaded depends on
      routines that are part of another firmware package, but that
      firmware package is not available.

   wrongDependencyVersion: The firmware package being loaded depends on
      routines that are part of the another firmware package, and the
      available version of that package has an older version number than
      is required.  The available firmware package does not fulfill the
      dependencies.

   insufficientMemory: The firmware package could not be loaded because
      the hardware module did not have sufficient memory.

   badFirmware: The signature on the firmware package was validated, but
      the firmware package itself was not in an acceptable format.  The
      details will be specific to each hardware module.  For example, a
      hardware module that is composed of multiple firmware-programmable
      components could not find the internal tagging within the firmware
      package to distribute executable code to each of the components.






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   unsupportedParameters: The signature on the firmware package could
      not be validated because the signer used signature algorithm
      parameters that are not supported by the hardware module signature
      verification routines.

   breaksDependency: Another firmware package has a dependency that can
      no longer be satisfied if the firmware package being loaded is
      accepted.

   otherError: An error occurred that does not fit any of the previous
      error codes.

4.2.  Signed Attributes

   The hardware module MUST digitally sign a collection of attributes
   along with the firmware package load error report.  Each attribute in
   the collection MUST be DER encoded [X.509-88].  The syntax for
   attributes is defined in [CMS], and it was repeated in Section 2.2
   for convenience.

   Each of the attributes used with this profile has a single attribute
   value, even though the syntax is defined as a SET OF AttributeValue.
   There MUST be exactly one instance of AttributeValue present.

   The SignedAttributes syntax within signerInfo is defined as a SET OF
   Attributes.  The SignedAttributes MUST include only one instance of
   any particular attribute.

   The hardware module MUST include the content-type and message-digest
   attributes.  If the hardware module includes a real-time clock, then
   the hardware module SHOULD also include the signing-time attribute.
   The hardware module MAY include any other attribute that it deems
   appropriate.

4.2.1.  Content Type

   The hardware module MUST include a content-type attribute with the
   value of id-ct-firmwareLoadError (1.2.840.113549.1.9.16.1.18).
   Section 11.1 of [CMS] defines the content-type attribute.

4.2.2.  Message Digest

   The hardware module MUST include a message-digest attribute, having
   as its value the message digest of the FirmwarePackageLoadError
   content.  Section 11.2 of [CMS] defines the message-digest attribute.






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4.2.3.  Signing Time

   If the hardware module includes a real-time clock, then hardware
   module SHOULD include a signing-time attribute, specifying the time
   at which the firmware package load error report was generated.
   Section 11.3 of [CMS] defines the signing-time attribute.

5.  Hardware Module Name

   Support for firmware package load receipts, as discussed in Section
   3, is OPTIONAL, and support for the firmware package load error
   reports, as discussed in Section 4, is OPTIONAL.  Hardware modules
   that support receipt or error report generation MUST have unique
   serial numbers.  Further, hardware modules that support signed
   receipt or error report generation MUST have private signature keys
   and corresponding signature validation certificates [PROFILE] or
   their designators.  The conventions for hardware module naming in the
   signature validation certificates are specified in this section.

   The hardware module vendor or a trusted third party MUST issue the
   signature validation certificate prior to deployment of the hardware
   module.  The certificate is likely to be issued at the time of
   manufacture.  The subject alternative name in this certificate
   identifies the hardware module.  The subject distinguished name is
   empty, but a critical subject alternative name extension contains the
   hardware module name, using the otherName choice within the
   GeneralName structure.

   The hardware module name form is identified by the id-on-
   hardwareModuleName object identifier:

      id-on-hardwareModuleName OBJECT IDENTIFIER ::= {
        iso(1) identified-organization(3) dod(6) internet(1) security(5)
        mechanisms(5) pkix(7) on(8) 4 }

   A HardwareModuleName is composed of an object identifier and an octet
   string:

      HardwareModuleName ::= SEQUENCE {
        hwType OBJECT IDENTIFIER,
        hwSerialNum OCTET STRING }

   The fields of the HardwareModuleName type have the following
   meanings:

   hwType is an object identifier that identifies the type of hardware
      module.  A unique object identifier names a hardware model and
      revision.



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   hwSerialNum is the serial number of the hardware module.  No
      particular structure is imposed on the serial number; it need not
      be an integer.  However, the combination of the hwType and
      hwSerialNum uniquely identifies the hardware module.

6.  Security Considerations

   This document describes the use of the Cryptographic Message Syntax
   (CMS) to protect firmware packages; therefore, the security
   considerations discussed in [CMS] apply to this specification as
   well.

   The conventions specified in this document raise a few security
   considerations of their own.

6.1.  Cryptographic Keys and Algorithms

   Private signature keys must be protected.  Compromise of the private
   key used to sign firmware packages permits unauthorized parties to
   generate firmware packages that are acceptable to hardware modules.
   Compromise of the hardware module private key allows unauthorized
   parties to generate signed firmware package load receipts and error
   reports.

   The firmware-decryption key must be protected.  Compromise of the key
   may result in the disclosure of the firmware package to unauthorized
   parties.

   Cryptographic algorithms become weaker with time.  As new
   cryptanalysis techniques are developed and computing performance
   improves, the work factor to break a particular cryptographic
   algorithm will be reduced.  The ability to change the firmware
   package provides an opportunity to update or replace cryptographic
   algorithms.  Although this capability is desirable, cryptographic
   algorithm replacement can lead to interoperability failures.
   Therefore, the rollout of new cryptographic algorithms must be
   managed.  Generally, the previous generation of cryptographic
   algorithms and their replacements need to be supported at the same
   time in order to facilitate an orderly transition.

6.2.  Random Number Generation

   When firmware packages are encrypted, the source of the firmware
   package must randomly generate firmware-encryption keys.  Also, the
   generation of public/private signature key pairs relies on a random
   numbers.  The use of inadequate pseudo-random number generators
   (PRNGs) to generate cryptographic keys can result in little or no
   security.  An attacker may find it much easier to reproduce the PRNG



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   environment that produced the keys, searching the resulting small set
   of possibilities, rather than brute-force searching the whole key
   space.  The generation of quality random numbers is difficult.  RFC
   4086 [RANDOM] offers important guidance in this area.

6.3.  Stale Firmware Package Version Number

   The firmware signer determines whether a stale version number is
   included.  The policy of the firmware signer needs to consider many
   factors.  Consider the flaw found by Ian Goldberg and David Wagner in
   the random number generator of the Netscape browser in 1996 [DDJ].
   This flaw completely undermines confidentiality protection.  A
   firmware signer might use the stale version number to ensure that
   upgraded hardware modules do not resume use of the flawed firmware.
   However, another firmware signer may not consider this an appropriate
   situation to employ the stale version number, preferring to delegate
   this decision to someone closer to the operation of the hardware
   module.  Such a person is likely to be in a better position to
   evaluate whether other bugs introduced in the newer firmware package
   impose worse operational concerns than the confidentiality concern
   caused by the flawed random number generator.  For example, a user
   who never uses the encryption feature of the flawed Netscape browser
   will determine the most appropriate version to use without
   considering the random number flaw or its fix.

   The stale version number is especially useful when the security
   interests of the person choosing which firmware package version to
   load into a particular hardware module do not align with the security
   interests of the firmware package signer.  For example, stale version
   numbers may be useful in hardware modules that provide digital rights
   management (DRM).  Also, stale version numbers will be useful when
   the deployment organization (as opposed to the firmware package
   vendor) is the firmware signer.  Further, stale version numbers will
   be useful for firmware packages that need to be trusted to implement
   organizational (as opposed to the deployment organization) security
   policy, regardless of whether the firmware signer is the deployment
   organization or the vendor.  For example, hardware devices employed
   by the military will probably make use of stale version numbers.

   The use of a stale version number in a firmware package that employs
   the preferred firmware package name form cannot completely prevent
   subsequent use of the stale firmware package.  Despite this
   shortcoming, the feature is included since it is useful in some
   important situations.  By loading different types of firmware
   packages, each with its own stale firmware package version number
   until the internal storage for the stale version number is exceeded,
   the user can circumvent the mechanism.  Consider a hardware module




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   that has storage for two stale version numbers.  Suppose that FWPKG-A
   version 3 is loaded, indicating that FWPKG-A version 2 is stale.  The
   user can sequentially load the following:

      - FWPKG-B version 8, indicating that FWPKG-B version 4 is stale.
          (Note: The internal storage indicates that FWPKG-A version 2
           and FWPKG-B version 4 are stale.)

      - FWPKG-C version 5, indicating that FWPKG-C version 3 is stale.
          (Note: The internal storage indicates that FWPKG-B version 4
           and FWPKG-C version 3 are stale.)

      - FWPKG-A version 2.

   Because many hardware modules are expected to have very few firmware
   packages written for them, the stale firmware package version feature
   provides important protections.  The amount of non-volatile storage
   that needs to be dedicated to saving firmware package identifiers and
   version numbers depends on the number of firmware packages that are
   likely to be developed for the hardware module.

   The use of legacy firmware package name form does not improve this
   situation.  In fact, the legacy firmware package names are usually
   larger than an object identifier.  Thus, comparable stale version
   protection requires more memory.

   A firmware signer can ensure that stale version numbers are honored
   by limiting the number of different types of firmware packages that
   are signed.  If all of the hardware modules are able to store a stale
   version number for each of the different types of firmware package,
   then the hardware module will be able to provide the desired
   protection.  This requires the firmware signer to have a deep
   understanding of all of the hardware modules that might accept the
   firmware package.

6.4.  Community Identifiers

   When a firmware package includes a community identifier, the
   confidence that the package is only used by the intended community
   depends on the mechanism used to configure community membership.
   This document does not specify a mechanism for the assignment of
   community membership to hardware modules, and the various
   alternatives have different security properties.  Also, the authority
   that makes community identifier assignments to hardware modules might
   be different than the authority that generates firmware packages.






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7.  References

7.1.  Normative References

   [COMPRESS]   Gutmann, P., "Compressed Data Content Type for
                Cryptographic Message Syntax (CMS)", RFC 3274, June
                2002.

   [CMS]        Housley, R., "Cryptographic Message Syntax (CMS)", RFC
                3852, July 2004.

   [ESS]        Hoffman, P., "Enhanced Security Services for S/MIME",
                RFC 2634, June 1999.

   [PROFILE]    Housley, R., Polk, W., Ford, W., and D. Solo, "Internet
                X.509 Public Key Infrastructure Certificate and
                Certificate Revocation List (CRL) Profile", RFC 3280,
                April 2002.

   [SHA1]       National Institute of Standards and Technology.  FIPS
                Pub 180-1: Secure Hash Standard.  17 April 1995.

   [STDWORDS]   Bradner, S., "Key words for use in RFCs to Indicate
                Requirement Levels", BCP 14, RFC 2119, March 1997.

   [UTF-8]      Yergeau, F., "UTF-8, a transformation format of ISO
                10646", STD 63, RFC 3629, November 2003.

   [X.208-88]   CCITT.  Recommendation X.208: Specification of Abstract
                Syntax Notation One (ASN.1).  1988.

   [X.209-88]   CCITT.  Recommendation X.209: Specification of Basic
                Encoding Rules for Abstract Syntax Notation One (ASN.1).
                1988.

   [X.509-88]   CCITT.  Recommendation X.509: The Directory -
                Authentication Framework.  1988.

7.2.  Informative References

   [ACPROFILE]  Farrell, S. and R. Housley, "An Internet Attribute
                Certificate Profile for Authorization", RFC 3281, April
                2002.

   [AES]        National Institute of Standards and Technology.  FIPS
                Pub 197:  Advanced Encryption Standard (AES).  26
                November 2001.




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   [DDJ]        Goldberg, I. and D. Wagner.  "Randomness and the
                Netscape Browser."  Dr. Dobb's Journal, January 1996.

   [DPD&DPV]    Pinkas, D. and R. Housley, "Delegated Path Validation
                and Delegated Path Discovery Protocol Requirements", RFC
                3379, September 2002.

   [OCSP]       Myers, M., Ankney, R., Malpani, A., Galperin, S., and C.
                Adams, "X.509 Internet Public Key Infrastructure Online
                Certificate Status Protocol - OCSP", RFC 2560, June
                1999.

   [PKCS#6]     RSA Laboratories.  PKCS #6: Extended-Certificate Syntax
                Standard, Version 1.5.  November 1993.

   [RANDOM]     Eastlake, D., 3rd, Schiller, J., and S. Crocker,
                "Randomness Requirements for Security", BCP 106, RFC
                4086, June 2005.

   [SECREQMTS]  National Institute of Standards and Technology.  FIPS
                Pub 140-2: Security Requirements for Cryptographic
                Modules.  25 May 2001.

   [X.509-97]   ITU-T.  Recommendation X.509: The Directory -
                Authentication Framework.  1997.

   [X.509-00]   ITU-T.  Recommendation X.509: The Directory -
                Authentication Framework.  2000.























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Appendix A: ASN.1 Module

   The ASN.1 module contained in this appendix defines the structures
   that are needed to implement the CMS-based firmware package wrapper.
   It is expected to be used in conjunction with the ASN.1 modules in
   [CMS], [COMPRESS], and [PROFILE].


   CMSFirmwareWrapper
       { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1)
         pkcs-9(9) smime(16) modules(0) cms-firmware-wrap(22) }

   DEFINITIONS IMPLICIT TAGS ::= BEGIN

   IMPORTS
       EnvelopedData
       FROM CryptographicMessageSyntax -- [CMS]
            { iso(1) member-body(2) us(840) rsadsi(113549)
              pkcs(1) pkcs-9(9) smime(16) modules(0) cms-2004(24) };


   -- Firmware Package Content Type and Object Identifier

   id-ct-firmwarePackage OBJECT IDENTIFIER ::= {
     iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
     smime(16) ct(1) 16 }

   FirmwarePkgData ::= OCTET STRING


   -- Firmware Package Signed Attributes and Object Identifiers

   id-aa-firmwarePackageID OBJECT IDENTIFIER ::= {
     iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
     smime(16) aa(2) 35 }

   FirmwarePackageIdentifier ::= SEQUENCE {
     name PreferredOrLegacyPackageIdentifier,
     stale PreferredOrLegacyStalePackageIdentifier OPTIONAL }

   PreferredOrLegacyPackageIdentifier ::= CHOICE {
     preferred PreferredPackageIdentifier,
     legacy OCTET STRING }

   PreferredPackageIdentifier ::= SEQUENCE {
     fwPkgID OBJECT IDENTIFIER,
     verNum INTEGER (0..MAX) }




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   PreferredOrLegacyStalePackageIdentifier ::= CHOICE {
     preferredStaleVerNum INTEGER (0..MAX),
     legacyStaleVersion OCTET STRING }


   id-aa-targetHardwareIDs OBJECT IDENTIFIER ::= {
     iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
     smime(16) aa(2) 36 }

   TargetHardwareIdentifiers ::= SEQUENCE OF OBJECT IDENTIFIER


   id-aa-decryptKeyID OBJECT IDENTIFIER ::= {
     iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
     smime(16) aa(2) 37 }

   DecryptKeyIdentifier ::= OCTET STRING


   id-aa-implCryptoAlgs OBJECT IDENTIFIER ::= {
     iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
     smime(16) aa(2) 38 }

   ImplementedCryptoAlgorithms ::= SEQUENCE OF OBJECT IDENTIFIER

   id-aa-implCompressAlgs OBJECT IDENTIFIER ::= {
     iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
     smime(16) aa(2) 43 }

   ImplementedCompressAlgorithms ::= SEQUENCE OF OBJECT IDENTIFIER


   id-aa-communityIdentifiers OBJECT IDENTIFIER ::= {
     iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
     smime(16) aa(2) 40 }

   CommunityIdentifiers ::= SEQUENCE OF CommunityIdentifier

   CommunityIdentifier ::= CHOICE {
     communityOID OBJECT IDENTIFIER,
     hwModuleList HardwareModules }

   HardwareModules ::= SEQUENCE {
     hwType OBJECT IDENTIFIER,
     hwSerialEntries SEQUENCE OF HardwareSerialEntry }






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RFC 4108         Using CMS to Protect Firmware Packages      August 2005


   HardwareSerialEntry ::= CHOICE {
     all NULL,
     single OCTET STRING,
     block SEQUENCE {
       low OCTET STRING,
       high OCTET STRING } }


   id-aa-firmwarePackageInfo OBJECT IDENTIFIER ::= {
     iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
     smime(16) aa(2) 42 }

   FirmwarePackageInfo ::= SEQUENCE {
     fwPkgType INTEGER OPTIONAL,
     dependencies SEQUENCE OF
       PreferredOrLegacyPackageIdentifier OPTIONAL }


   -- Firmware Package Unsigned Attributes and Object Identifiers

   id-aa-wrappedFirmwareKey OBJECT IDENTIFIER ::= {
     iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
     smime(16) aa(2) 39 }

   WrappedFirmwareKey ::= EnvelopedData


   -- Firmware Package Load Receipt Content Type and Object Identifier

   id-ct-firmwareLoadReceipt OBJECT IDENTIFIER ::= {
     iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
     smime(16) ct(1) 17 }

   FirmwarePackageLoadReceipt ::= SEQUENCE {
     version FWReceiptVersion DEFAULT v1,
     hwType OBJECT IDENTIFIER,
     hwSerialNum OCTET STRING,
     fwPkgName PreferredOrLegacyPackageIdentifier,
     trustAnchorKeyID OCTET STRING OPTIONAL,
     decryptKeyID [1] OCTET STRING OPTIONAL }

   FWReceiptVersion ::= INTEGER { v1(1) }









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   -- Firmware Package Load Error Report Content Type
   -- and Object Identifier

   id-ct-firmwareLoadError OBJECT IDENTIFIER ::= {
     iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9)
     smime(16) ct(1) 18 }

   FirmwarePackageLoadError ::= SEQUENCE {
     version FWErrorVersion DEFAULT v1,
     hwType OBJECT IDENTIFIER,
     hwSerialNum OCTET STRING,
     errorCode FirmwarePackageLoadErrorCode,
     vendorErrorCode VendorLoadErrorCode OPTIONAL,
     fwPkgName PreferredOrLegacyPackageIdentifier OPTIONAL,
     config [1] SEQUENCE OF CurrentFWConfig OPTIONAL }

   FWErrorVersion ::= INTEGER { v1(1) }

   CurrentFWConfig ::= SEQUENCE {
     fwPkgType INTEGER OPTIONAL,
     fwPkgName PreferredOrLegacyPackageIdentifier }

   FirmwarePackageLoadErrorCode ::= ENUMERATED {
     decodeFailure                (1),
     badContentInfo               (2),
     badSignedData                (3),
     badEncapContent              (4),
     badCertificate               (5),
     badSignerInfo                (6),
     badSignedAttrs               (7),
     badUnsignedAttrs             (8),
     missingContent               (9),
     noTrustAnchor               (10),
     notAuthorized               (11),
     badDigestAlgorithm          (12),
     badSignatureAlgorithm       (13),
     unsupportedKeySize          (14),
     signatureFailure            (15),
     contentTypeMismatch         (16),
     badEncryptedData            (17),
     unprotectedAttrsPresent     (18),
     badEncryptContent           (19),
     badEncryptAlgorithm         (20),
     missingCiphertext           (21),
     noDecryptKey                (22),
     decryptFailure              (23),
     badCompressAlgorithm        (24),
     missingCompressedContent    (25),



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RFC 4108         Using CMS to Protect Firmware Packages      August 2005


     decompressFailure           (26),
     wrongHardware               (27),
     stalePackage                (28),
     notInCommunity              (29),
     unsupportedPackageType      (30),
     missingDependency           (31),
     wrongDependencyVersion      (32),
     insufficientMemory          (33),
     badFirmware                 (34),
     unsupportedParameters       (35),
     breaksDependency            (36),
     otherError                  (99) }

   VendorLoadErrorCode ::= INTEGER


   -- Other Name syntax for Hardware Module Name

   id-on-hardwareModuleName OBJECT IDENTIFIER ::= {
     iso(1) identified-organization(3) dod(6) internet(1) security(5)
     mechanisms(5) pkix(7) on(8) 4 }

   HardwareModuleName ::= SEQUENCE {
     hwType OBJECT IDENTIFIER,
     hwSerialNum OCTET STRING }


   END

Author's Address

   Russell Housley
   Vigil Security, LLC
   918 Spring Knoll Drive
   Herndon, VA 20170
   USA

   EMail: housley@vigilsec.com













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Full Copyright Statement

   Copyright (C) The Internet Society (2005).

   This document is subject to the rights, licenses and restrictions
   contained in BCP 78, and except as set forth therein, the authors
   retain all their rights.

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   "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
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   The IETF invites any interested party to bring to its attention any
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Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.







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