path: root/doc/rfc/rfc9102.txt

Independent Submission                                       V. Dukhovni
Request for Comments: 9102                                     Two Sigma
Category: Experimental                                          S. Huque
ISSN: 2070-1721                                               Salesforce
                                                               W. Toorop
                                                              NLnet Labs
                                                              P. Wouters
                                                                   Aiven
                                                                M. Shore
                                                                  Fastly
                                                             August 2021


                       TLS DNSSEC Chain Extension

Abstract

   This document describes an experimental TLS extension for the in-band
   transport of the complete set of records that can be validated by
   DNSSEC and that are needed to perform DNS-Based Authentication of
   Named Entities (DANE) of a TLS server.  This extension obviates the
   need to perform separate, out-of-band DNS lookups.  When the
   requisite DNS records do not exist, the extension conveys a denial-
   of-existence proof that can be validated.

   This experimental extension is developed outside the IETF and is
   published here to guide implementation of the extension and to ensure
   interoperability among implementations.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for examination, experimental implementation, and
   evaluation.

   This document defines an Experimental Protocol for the Internet
   community.  This is a contribution to the RFC Series, independently
   of any other RFC stream.  The RFC Editor has chosen to publish this
   document at its discretion and makes no statement about its value for
   implementation or deployment.  Documents approved for publication by
   the RFC Editor are not candidates for any level of Internet Standard;
   see Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   https://www.rfc-editor.org/info/rfc9102.

Copyright Notice

   Copyright (c) 2021 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.

Table of Contents

   1.  Introduction
     1.1.  Scope of the Experiment
     1.2.  Requirements Notation
   2.  DNSSEC Authentication Chain Extension
     2.1.  Protocol, TLS 1.2
     2.2.  Protocol, TLS 1.3
     2.3.  DNSSEC Authentication Chain Data
       2.3.1.  Authenticated Denial of Existence
   3.  Construction of Serialized Authentication Chains
   4.  Caching and Regeneration of the Authentication Chain
   5.  Expired Signatures in the Authentication Chain
   6.  Verification
   7.  Extension Pinning
   8.  Trust Anchor Maintenance
   9.  Virtual Hosting
   10. Operational Considerations
   11. Security Considerations
   12. IANA Considerations
   13. References
     13.1.  Normative References
     13.2.  Informative References
   Appendix A.  Test Vectors
     A.1.  "_443._tcp.www.example.com"
     A.2.  "_25._tcp.example.com" NSEC Wildcard
     A.3.  "_25._tcp.example.org" NSEC3 Wildcard
     A.4.  "_443._tcp.www.example.org" CNAME
     A.5.  "_443._tcp.www.example.net" DNAME
     A.6.  "_25._tcp.smtp.example.com" NSEC Denial of Existence
     A.7.  "_25._tcp.smtp.example.org" NSEC3 Denial of Existence
     A.8.  "_443._tcp.www.insecure.example" NSEC3 Opt-Out Insecure
           Delegation
   Acknowledgments
   Authors' Addresses

1.  Introduction

   This document describes an experimental TLS [RFC5246] [RFC8446]
   extension for in-band transport of the complete set of resource
   records (RRs) validated by DNSSEC [RFC4033] [RFC4034] [RFC4035].
   This extension enables a TLS client to perform DANE authentication
   [RFC6698] [RFC7671] of a TLS server without the need to perform out-
   of-band DNS lookups.  Retrieval of the required DNS records may be
   unavailable to the client [DISCOVERY] or may incur undesirable
   additional latency.

   The extension described here allows a TLS client to request that the
   TLS server return the DNSSEC authentication chain corresponding to
   its DNSSEC-validated DANE TLSA resource record set (RRset) or
   authenticated denial of existence of such an RRset (as described in
   Section 2.3.1).  If the server supports this extension, it performs
   the appropriate DNS queries, builds the authentication chain, and
   returns it to the client.  The server will typically use a previously
   cached authentication chain, but it will need to rebuild it
   periodically as described in Section 4.  The client then
   authenticates the chain using a preconfigured DNSSEC trust anchor.

   In the absence of TLSA records, this extension conveys the required
   authenticated denial of existence.  Such proofs are needed to
   securely signal that specified TLSA records are not available so that
   TLS clients can safely fall back to authentication based on Public
   Key Infrastructure X.509 (PKIX, sometimes called WebPKI) if allowed
   by local policy.  These proofs are also needed to avoid downgrade
   from opportunistic authenticated TLS (when DANE TLSA records are
   present) to unauthenticated opportunistic TLS (in the absence of
   DANE).  Denial-of-existence records are also used by the TLS client
   to clear extension pins that are no longer relevant, as described in
   Section 7.

   This extension supports DANE authentication of either X.509
   certificates or raw public keys, as described in the DANE
   specification [RFC6698] [RFC7671] [RFC7250].

   This extension also mitigates against an unknown key share (UKS)
   attack [DANE-UKS] when using raw public keys since the server commits
   to its DNS name (normally found in its certificate) via the content
   of the returned TLSA RRset.

   This experimental extension is developed outside the IETF and is
   published here to guide implementation of the extension and to ensure
   interoperability among implementations.

1.1.  Scope of the Experiment

   The mechanism described in this document is intended to be used with
   applications on the wider internet.  One application of TLS well
   suited for the TLS DNSSEC Chain extension is DNS over TLS [RFC7858].
   In fact, one of the authentication methods for DNS over TLS _is_ the
   mechanism described in this document, as specified in Section 8.2.2
   of [RFC8310].

   The need for this mechanism when using DANE to authenticate a DNS-
   over-TLS resolver is obvious, since DNS may not be available to
   perform the required DNS lookups.  Other applications of TLS would
   benefit from using this mechanism as well.  The client sides of those
   applications would not be required to be used on endpoints with a
   working DNSSEC resolver in order for them to use the DANE
   authentication of the TLS service.  Therefore, we invite other TLS
   services to try out this mechanism as well.

   In the TLS Working Group, concerns have been raised that the pinning
   technique as described in Section 7 would complicate deployability of
   the TLS DNSSEC chain extension.  The goal of the experiment is to
   study these complications in real-world deployments.  This experiment
   hopefully will give the TLS Working Group some insight into whether
   or not this is a problem.

   If the experiment is successful, it is expected that the findings of
   the experiment will result in an updated document for Standards Track
   approval.

1.2.  Requirements Notation

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

2.  DNSSEC Authentication Chain Extension

2.1.  Protocol, TLS 1.2

   A client MAY include an extension of type "dnssec_chain" in the
   (extended) ClientHello.  The "extension_data" field of this extension
   consists of the server's 16-bit TCP port number in network (big-
   endian) byte order.  Clients sending this extension MUST also send
   the Server Name Identification (SNI) extension [RFC6066].  Together,
   these make it possible for the TLS server to determine which
   authenticated TLSA RRset chain needs to be used for the
   "dnssec_chain" extension.

   When a server that implements (and is configured to enable the use
   of) this extension receives a "dnssec_chain" extension in the
   ClientHello, it MUST first check whether the requested TLSA RRset
   (based on the port number in this extension and hostname in the SNI
   extension) is associated with the server.  If the extension, the SNI
   hostname, or the port number is unsupported, the server's extended
   ServerHello message MUST NOT include the "dnssec_chain" extension.

   Otherwise, the server's extended ServerHello message MUST contain a
   serialized authentication chain using the format described below.  If
   the server does not have access to the requested DNS chain -- for
   example, due to a misconfiguration or expired chain -- the server
   MUST omit the extension rather than send an incomplete chain.
   Clients that are expecting this extension MUST interpret this as a
   downgrade attack and MUST abort the TLS connection.  Therefore,
   servers MUST send denial-of-existence proofs unless, for the
   particular application protocol or service, clients are expected to
   continue even in the absence of such a proof.  As with all TLS
   extensions, if the server does not support this extension, it will
   not return any authentication chain.

   The set of supported combinations of a port number and SNI name may
   be configured explicitly by server administrators or could be
   inferred from the available certificates combined with a list of
   supported ports.  It is important to note that the client's notional
   port number may be different from the actual port on which the server
   is receiving connections.

   Differences between the client's notional port number and the actual
   port at the server could be a result of intermediate systems
   performing network address translation or a result of a redirect via
   HTTPS or SVCB records (both defined in [DNSOP-SVCB-HTTPS]).

   Though a DNS zone's HTTPS or SVCB records may be signed, a client
   using this protocol might not have direct access to a validating
   resolver and might not be able to check the authenticity of the
   target port number or hostname.  In order to avoid downgrade attacks
   via forged DNS records, the SNI name and port number inside the
   client extension MUST be based on the original SNI name and port and
   MUST NOT be taken from the encountered HTTPS or SVCB record.  The
   client supporting this document and HTTPS or SVCB records MUST still
   use the HTTPS or SVCB records to select the target transport
   endpoint.  Servers supporting this extension that are targets of
   HTTPS or SVCB records MUST be provisioned to process client
   extensions based on the client's logical service endpoint's SNI name
   and port as it is prior to HTTPS or SVCB indirection.

2.2.  Protocol, TLS 1.3

   In TLS 1.3 [RFC8446], when the server receives the "dnssec_chain"
   extension, it adds its "dnssec_chain" extension to the extension
   block of the Certificate message containing the end-entity
   certificate being validated rather than to the extended ServerHello
   message.

   The extension protocol behavior otherwise follows that specified for
   TLS version 1.2 [RFC5246].

2.3.  DNSSEC Authentication Chain Data

   The "extension_data" field of the client's "dnssec_chain" extension
   MUST contain the server's 16-bit TCP port number in network (big-
   endian) byte order:

       struct {
           uint16 PortNumber;
       } DnssecChainExtension;

   The "extension_data" field of the server's "dnssec_chain" extension
   MUST contain a DNSSEC authentication chain encoded in the following
   form:

       struct {
           uint16 ExtSupportLifetime;
           opaque AuthenticationChain<1..2^16-1>
       } DnssecChainExtension;

   The ExtSupportLifetime value is the number of hours that the TLS
   server has committed itself to serving this extension.  A value of
   zero prohibits the client from unilaterally requiring ongoing use of
   the extension based on prior observation of its use (extension
   pinning).  This is further described in Section 7.

   The AuthenticationChain is composed of a sequence of uncompressed
   wire format DNS RRs (including all requisite RRSIG RRs [RFC4034]) in
   no particular order.  The format of the resource record is described
   in [RFC1035], Section 3.2.1.

       RR = { owner, type, class, TTL, RDATA length, RDATA }

   The order of returned RRs is unspecified, and a TLS client MUST NOT
   assume any ordering of RRs.

   Use of DNS wire format records enables easier generation of the data
   structure on the server and easier verification of the data on the
   client by means of existing DNS library functions.

   The returned RRsets MUST contain either the TLSA RRset or the
   associated denial-of-existence proof of the configured (and
   requested) SNI name and port.  In either case, the chain of RRsets
   MUST be accompanied by the full set of DNS records needed to
   authenticate the TLSA record set or its denial of existence up the
   DNS hierarchy to either the root zone or another trust anchor
   mutually configured by the TLS server and client.

   When some subtree in the chain is subject to redirection via DNAME
   records, the associated inferred CNAME records need not be included.
   They can be inferred by the DNS validation code in the client.  Any
   applicable ordinary CNAME records that are not synthesized from DNAME
   records MUST be included along with their RRSIGs.

   In case of a server-side DNS problem, servers may be unable to
   construct the authentication chain and would then have no choice but
   to omit the extension.

   In the case of a denial-of-existence response, the authentication
   chain MUST include all DNSSEC-signed records, starting with those
   from the trust anchor zone, that chain together to reach a proof of
   either:

   *  the nonexistence of the TLSA records (possibly redirected via
      aliases) or

   *  an insecure delegation above or at the (possibly redirected) owner
      name of the requested TLSA RRset.

   Names that are aliased via CNAME and/or DNAME records may involve
   multiple branches of the DNS tree.  In this case, the authentication
   chain structure needs to include DS and DNSKEY record sets that cover
   all the necessary branches.

   The returned chain SHOULD also include the DNSKEY RRsets of all
   relevant trust anchors (typically just the root DNS zone).  Though
   the same trust anchors are presumably also preconfigured in the TLS
   client, including them in the response from the server permits TLS
   clients to use the automated trust anchor rollover mechanism defined
   in [RFC5011] to update their configured trust anchors.

   Barring prior knowledge of particular trust anchors that the server
   shares with its clients, the chain constructed by the server MUST be
   extended as closely as possible to the root zone.  Truncation of the
   chain at some intermediate trust anchor is generally only appropriate
   inside private networks where all clients and the server are expected
   to be configured with DNS trust anchors for one or more non-root
   domains.

   The following is an example of the records in the AuthenticationChain
   structure for the HTTPS server at "www.example.com", where there are
   zone cuts at "com" and "example.com" (record data are omitted here
   for brevity):

   _443._tcp.www.example.com. TLSA
   RRSIG(_443._tcp.www.example.com. TLSA)
   example.com. DNSKEY
   RRSIG(example.com. DNSKEY)
   example.com. DS
   RRSIG(example.com. DS)
   com. DNSKEY
   RRSIG(com. DNSKEY)
   com. DS
   RRSIG(com. DS)
   . DNSKEY
   RRSIG(. DNSKEY)

   The following is an example of denial of existence for a TLSA RRset
   at "_443._tcp.www.example.com".  The NSEC record in this example
   asserts the nonexistence of both the requested RRset and any
   potentially relevant wildcard records.

   www.example.com. IN NSEC example.com. A NSEC RRSIG
   RRSIG(www.example.com. NSEC)
   example.com. DNSKEY
   RRSIG(example.com. DNSKEY)
   example.com. DS
   RRSIG(example.com. DS)
   com. DNSKEY
   RRSIG(com. DNSKEY)
   com. DS
   RRSIG(com. DS)
   . DNSKEY
   RRSIG(. DNSKEY)

   The following is an example of (hypothetical) insecure delegation of
   "example.com" from the ".com" zone.  This example shows NSEC3 records
   [RFC5155] with opt-out.

   ; covers example.com
   onib9mgub9h0rml3cdf5bgrj59dkjhvj.com. NSEC3 (1 1 0 -
     onib9mgub9h0rml3cdf5bgrj59dkjhvl NS DS RRSIG)
   RRSIG(onib9mgub9h0rml3cdf5bgrj59dkjhvj.com. NSEC3)
   ; covers *.com
   3rl2r262eg0n1ap5olhae7mah2ah09hi.com. NSEC3 (1 1 0 -
     3rl2r262eg0n1ap5olhae7mah2ah09hk NS DS RRSIG)
   RRSIG(3rl2r262eg0n1ap5olhae7mah2ah09hj.com. NSEC3)
   ; closest-encloser "com"
   ck0pojmg874ljref7efn8430qvit8bsm.com. NSEC3 (1 1 0 -
     ck0pojmg874ljref7efn8430qvit8bsm.com
     NS SOA RRSIG DNSKEY NSEC3PARAM)
   RRSIG(ck0pojmg874ljref7efn8430qvit8bsm.com. NSEC3)
   com. DNSKEY
   RRSIG(com. DNSKEY)
   com. DS
   RRSIG(com. DS)
   . DNSKEY
   RRSIG(. DNSKEY)

2.3.1.  Authenticated Denial of Existence

   TLS servers that support this extension and respond to a request
   containing this extension that do not have a signed TLSA record for
   the configured (and requested) SNI name and port MUST instead return
   a DNSSEC chain that provides authenticated denial of existence for
   the configured SNI name and port.  A TLS client receiving proof of
   authenticated denial of existence MUST use an alternative method to
   verify the TLS server identity or close the connection.  Such an
   alternative could be the classic PKIX model of preinstalled root
   certificate authorities (CAs).

   Authenticated denial chains include NSEC or NSEC3 records that
   demonstrate one of the following facts:

   *  The TLSA record (after any DNSSEC-validated alias redirection)
      does not exist.

   *  There is no signed delegation to a DNS zone that is either an
      ancestor of or the same as the TLSA record name (after any DNSSEC-
      validated alias redirection).

3.  Construction of Serialized Authentication Chains

   This section describes a possible procedure for the server to use to
   build the serialized DNSSEC chain.

   When the goal is to perform DANE authentication [RFC6698] [RFC7671]
   of the server, the DNS record set to be serialized is a TLSA record
   set corresponding to the server's domain name, protocol, and port
   number.

   The domain name of the server MUST be that included in the TLS
   "server_name" (SNI) extension [RFC6066].  If the server does not
   recognize the SNI name as one of its own names but wishes to proceed
   with the handshake rather than abort the connection, the server MUST
   NOT send a "dnssec_chain" extension to the client.

   The name in the client's SNI extension MUST NOT be CNAME expanded by
   the server.  The TLSA base domain (Section 3 of [RFC6698]) SHALL be
   the hostname from the client's SNI extension, and the guidance in
   Section 7 of [RFC7671] does not apply.  See Section 9 for further
   discussion.

   The TLSA record to be queried is constructed by prepending
   underscore-prefixed port number and transport name labels to the
   domain name as described in [RFC6698].  The port number is taken from
   the client's "dnssec_chain" extension.  The transport name is "tcp"
   for TLS servers and "udp" for DTLS servers.  The port number label is
   the leftmost label, followed by the transport name label, followed by
   the server domain name (from SNI).

   The components of the authentication chain are typically built by
   starting at the target record set and its corresponding RRSIG, then
   traversing the DNS tree upwards towards the trust anchor zone
   (normally the DNS root).  For each zone cut, the DNSKEY, DS RRsets,
   and their signatures are added.  However, see Section 2.3 for
   specific processing needed for aliases.  If DNS response messages
   contain any domain names utilizing name compression [RFC1035], then
   they MUST be uncompressed prior to inclusion in the chain.

   Implementations of EDNS CHAIN query requests as specified in
   [RFC7901] may offer an easier way to obtain all of the chain data in
   one transaction with an upstream DNSSEC-aware recursive server.

4.  Caching and Regeneration of the Authentication Chain

   DNS records have Time To Live (TTL) parameters, and DNSSEC signatures
   have validity periods (specifically signature expiration times).
   After the TLS server constructs the serialized authentication chain,
   it SHOULD cache and reuse it in multiple TLS connection handshakes.
   However, it SHOULD refresh and rebuild the chain as TTL values
   require.  A server implementation could carefully track TTL
   parameters and requery component records in the chain
   correspondingly.  Alternatively, it could be configured to rebuild
   the entire chain at some predefined periodic interval that does not
   exceed the DNS TTLs of the component records in the chain.  If a
   record in the chain has a very short TTL (e.g., 0 up to a few
   seconds), the server MAY decide to serve the authentication chain a
   few seconds past the minimum TTL in the chain.  This allows an
   implementation to dedicate a process or single thread to building the
   authentication chain and reuse it for more than a single waiting TLS
   client before needing to rebuild the authentication chain.

5.  Expired Signatures in the Authentication Chain

   A server MAY look at the signature expiration of RRSIG records.
   While these should never expire before the TTL of the corresponding
   DNS record is reached, if this situation is nevertheless encountered,
   the server MAY lower the TTL to prevent serving expired RRSIGs if
   possible.  If the signatures are already expired, the server MUST
   still include these records in the authentication chain.  This allows
   the TLS client to either support a grace period for staleness or give
   a detailed error, either as a log message or a message to a potential
   interactive user of the TLS connection.  The TLS client SHOULD handle
   expired RRSIGs similarly to how it handles expired PKIX certificates.

6.  Verification

   A TLS client performing DANE-based verification might not need to use
   this extension.  For example, the TLS client could perform DNS
   lookups and DANE verification without this extension, or it could
   fetch authentication chains via another protocol.  If the TLS client
   already possesses a valid TLSA record, it MAY bypass use of this
   extension.  However, if it includes this extension, it MUST use the
   TLS server reply to update the extension pinning status of the TLS
   server's extension lifetime.  See Section 7.

   A TLS client making use of this specification that receives a valid
   DNSSEC authentication chain extension from a TLS server MUST use this
   information to perform DANE authentication of the TLS server.  In
   order to perform the validation, it uses the mechanism specified by
   the DNSSEC protocol [RFC4035] [RFC5155].  This mechanism is sometimes
   implemented in a DNSSEC validation engine or library.

   If the authentication chain validates, the TLS client then performs
   DANE authentication of the server according to the DANE TLS protocol
   [RFC6698] [RFC7671].

   Clients MAY cache the server's validated TLSA RRset to amortize the
   cost of receiving and validating the chain over multiple connections.
   The period of such caching MUST NOT exceed the TTL associated with
   those records.  A client that possesses a validated and unexpired
   TLSA RRset or the full chain in its cache does not need to send the
   "dnssec_chain" extension for subsequent connections to the same TLS
   server.  It can use the cached information to perform DANE
   authentication.

   Note that when a client and server perform TLS session resumption,
   the server sends no "dnssec_chain".  This is particularly clear with
   TLS 1.3, where the certificate message to which the chain might be
   attached is also not sent on resumption.

7.  Extension Pinning

   TLS applications can be designed to unconditionally mandate this
   extension.  Such TLS clients requesting this extension would abort a
   connection to a TLS server that does not respond with an extension
   reply that can be validated.

   However, in a mixed-use deployment of PKIX and DANE, there is the
   possibility that the security of a TLS client is downgraded from DANE
   to PKIX.  This can happen when a TLS client connection is intercepted
   and redirected to a rogue TLS server presenting a TLS certificate
   that is considered valid from a PKIX point of view but does not match
   the legitimate server's TLSA records.  By omitting this extension,
   such a rogue TLS server could downgrade the TLS client to validate
   the mis-issued certificate using only PKIX and not via DANE, provided
   the TLS client is also not able to fetch the TLSA records directly
   from DNS.

   The ExtSupportLifetime element of the extension provides a
   countermeasure against such downgrade attacks.  Its value represents
   the number of hours that the TLS server (or cluster of servers
   serving the same server name) commits to serving this extension in
   the future.  This is referred to as the "pinning time" or "extension
   pin" of the extension.  A non-zero extension pin value received MUST
   ONLY be used if the extension also contains a valid TLSA
   authentication chain that matches the server's certificate chain (the
   server passes DANE authentication based on the enclosed TLSA RRset).

   Any existing extension pin for the server instance (name and port)
   MUST be cleared on receipt of a valid denial of existence for the
   associated TLSA RRset.  The same also applies if the client obtained
   the denial-of-existence proof via another method, such as through
   direct DNS queries.  Based on the TLS client's local policy, it MAY
   then terminate the connection or MAY continue using PKIX-based server
   authentication.

   Extension pins MUST also be cleared upon the completion of a DANE-
   authenticated handshake with a server that returns a "dnssec_chain"
   extension with a zero ExtSupportLifetime.

   Upon completion of a fully validated handshake with a server that
   returns a "dnssec_chain" extension with a non-zero ExtSupport
   lifetime, the client MUST update any existing pin lifetime for the
   service (name and port) to a value that is not longer than that
   indicated by the server.  The client MAY, subject to local policy,
   create a previously nonexistent pin, again for a lifetime that is not
   longer than that indicated by the server.

   The extension support lifetime is not constrained by any DNS TTLs or
   RRSIG expirations in the returned chain.  The extension support
   lifetime is the time for which the TLS server is committing itself to
   serve the extension; it is not a validity time for the returned chain
   data.  During this period, the DNSSEC chain may be updated.
   Therefore, the ExtSupportLifetime value is not constrained by any DNS
   TTLs or RRSIG expirations in the returned chain.

   Clients MAY implement support for a subset of DANE certificate
   usages.  For example, clients may support only DANE-EE(3) and DANE-
   TA(2) [RFC7218], only PKIX-EE(1) and PKIX-TA(0), or all four.
   Clients that implement DANE-EE(3) and DANE-TA(2) MUST implement the
   relevant updates in [RFC7671].

   For a non-zero saved value ("pin") of the ExtSupportLifetime element
   of the extension, TLS clients that do not have a cached TLSA RRset
   with an unexpired TTL MUST use the extension for the associated name
   and port to obtain this information from the TLS server.  This TLS
   client then MUST require that the TLS server respond with this
   extension, which MUST contain a valid TLSA RRset or proof of
   nonexistence of the TLSA RRset that covers the requested name and
   port.  Note that a nonexistence proof or proof of insecure delegation
   will clear the pin.  The TLS client MUST require this for as long as
   the time period specified by the pin value, independent of the DNS
   TTLs.  During this process, if the TLS client fails to receive this
   information, it MUST either abort the connection or delay
   communication with the server via the TLS connection until it is able
   to obtain valid TLSA records (or proof of nonexistence) out of band,
   such as via direct DNS lookups.  If attempts to obtain the TLSA RRset
   out of band fail, the client MUST abort the TLS connection.  It MAY
   try a new TLS connection again (for example, using an exponential
   back-off timer) in an attempt to reach a different TLS server
   instance that does properly serve the extension.

   A TLS client that has a cached validated TLSA RRset and a valid non-
   zero extension pin time MAY still refrain from requesting the
   extension as long as it uses the cached TLSA RRset to authenticate
   the TLS server.  This RRset MUST NOT be used beyond its received TTL.
   Once the TLSA RRset's TTL has expired, the TLS client with a valid
   non-zero extension pin time MUST request the extension and MUST abort
   the TLS connection if the server responds without the extension.  A
   TLS client MAY attempt to obtain the valid TLSA RRset by some other
   means before initiating a new TLS connection.

   Note that requiring the extension is NOT the same as requiring the
   use of DANE TLSA records or even DNSSEC.  A DNS zone operator may at
   any time delete the TLSA records or even remove the DS records to
   disable the secure delegation of the server's DNS zone.  The TLS
   server will replace the chain with the corresponding denial-of-
   existence chain when it updates its cached TLSA authentication chain.
   The server's only obligation is continued support for this extension.

8.  Trust Anchor Maintenance

   The trust anchor may change periodically, e.g., when the operator of
   the trust anchor zone performs a DNSSEC key rollover.  TLS clients
   using this specification MUST implement a mechanism to keep their
   trust anchors up to date.  They could use the method defined in
   [RFC5011] to perform trust anchor updates in-band in TLS by tracking
   the introduction of new keys seen in the trust anchor DNSKEY RRset.
   However, alternative mechanisms external to TLS may also be utilized.
   Some operating systems may have a system-wide service to maintain and
   keep the root trust anchor up to date.  In such cases, the TLS client
   application could simply reference that as its trust anchor,
   periodically checking whether it has changed.  Some applications may
   prefer to implement trust anchor updates as part of their automated
   software updates.

9.  Virtual Hosting

   Delivery of application services is often provided by a third party
   on behalf of the domain owner (hosting customer).  Since the domain
   owner may want to be able to move the service between providers, non-
   zero support lifetimes for this extension should only be enabled by
   mutual agreement between the provider and domain owner.

   When CNAME records are employed to redirect network connections to
   the provider's network, as mentioned in Section 3, the server uses
   the client's SNI hostname as the TLSA base domain without CNAME
   expansion.  When the certificate chain for the service is managed by
   the provider, it is impractical to coordinate certificate changes by
   the provider with updates in the hosting customer's DNS.  Therefore,
   the TLSA RRset for the hosted domain is best configured as a CNAME
   from the customer's domain to a TLSA RRset that is managed by the
   provider as part of delivering the hosted service.  For example:

   ; Customer DNS
   www.example.com. IN CNAME node1.provider.example.
   _443._tcp.www.example.com. IN CNAME _dane443.node1.provider.example.
   ; Provider DNS
   node1.provider.example. IN A 192.0.2.1
   _dane443.node1.provider.example. IN TLSA 1 1 1 ...

   Clients that obtain TLSA records directly from DNS, bypassing this
   extension, may perform CNAME expansion as in Section 7 of [RFC7671].
   If TLSA records are associated with the fully expanded name, that
   name may be used as the TLSA base domain and SNI name for the TLS
   handshake.

   To avoid confusion, it is RECOMMENDED that server operators not
   publish TLSA RRs (_port._tcp. + base domain) based on the expanded
   CNAMEs used to locate their network addresses.  Instead, the server
   operator SHOULD publish TLSA RRs at an alternative DNS node (as in
   the example above), to which the hosting customer will publish a
   CNAME alias.  This results in all clients (whether they obtain TLSA
   records from DNS directly or employ this extension) seeing the same
   TLSA records and sending the same SNI name.

10.  Operational Considerations

   When DANE is being introduced incrementally into an existing PKIX
   environment, there may be scenarios in which DANE authentication for
   a server fails but PKIX succeeds, or vice versa.  What happens here
   depends on TLS client policy.  If DANE authentication fails, the
   client may decide to fall back to regular PKIX authentication.  In
   order to do so efficiently within the same TLS handshake, the TLS
   server needs to have provided the full X.509 certificate chain.  When
   TLS servers only support DANE-EE or DANE-TA modes, they have the
   option to send a much smaller certificate chain: just the EE
   certificate for the former and a short certificate chain from the
   DANE trust anchor to the EE certificate for the latter.  If the TLS
   server supports both DANE and regular PKIX and wants to allow
   efficient PKIX fallback within the same handshake, they should always
   provide the full X.509 certificate chain.

   When a TLS server operator wishes to no longer deploy this extension,
   it must properly decommission its use.  If a non-zero pin lifetime is
   presently advertised, it must first be changed to 0.  The extension
   can be disabled once all previously advertised pin lifetimes have
   expired.  Removal of TLSA records or even DNSSEC signing of the zone
   can be done at any time, but the server MUST still be able to return
   the associated denial-of-existence proofs to any clients that have
   unexpired pins.

   TLS clients MAY reduce the received extension pin value to a maximum
   set by local policy.  This can mitigate a theoretical yet unlikely
   attack where a compromised TLS server is modified to advertise a pin
   value set to the maximum of 7 years.  Care should be taken not to set
   a local maximum that is too short as that would reduce the downgrade
   attack protection that the extension pin offers.

   If the hosting provider intends to use end-entity TLSA records
   (certificate usage PKIX-EE(1) or DANE-EE(3)), then the simplest
   approach is to use the same key pair for all the certificates at a
   given hosting node and publish "1 1 1" or "3 1 1" RRs matching the
   common public key.  Since key rollover cannot be simultaneous across
   multiple certificate updates, there will be times when multiple "1 1
   1" (or "3 1 1") records will be required to match all the extant
   certificates.  Multiple TLSA records are, in any case, needed a few
   TTLs before certificate updates as explained in Section 8 of
   [RFC7671].

   If the hosting provider intends to use trust anchor TLSA records
   (certificate usage PKIX-TA(0) or DANE-TA(2)), then the same TLSA
   record can match all end-entity certificates issues by the
   certification authority in question and continues to work across end-
   entity certificate updates so long as the issuer certificate or
   public keys remain unchanged.  This can be easier to implement at the
   cost of greater reliance on the security of the selected
   certification authority.

   The provider can, of course, publish separate TLSA records for each
   customer, which increases the number of such RRsets that need to be
   managed but makes each one independent of the rest.

11.  Security Considerations

   The security considerations of the normatively referenced RFCs all
   pertain to this extension.  Since the server is delivering a chain of
   DNS records and signatures to the client, it MUST rebuild the chain
   in accordance with TTL and signature expiration of the chain
   components as described in Section 4.  TLS clients need roughly
   accurate time in order to properly authenticate these signatures.
   This could be achieved by running a time synchronization protocol
   like NTP [RFC5905] or SNTP [RFC5905], which are already widely used
   today.  TLS clients MUST support a mechanism to track and roll over
   the trust anchor key or be able to avail themselves of a service that
   does this, as described in Section 8.  Security considerations
   related to mandating the use of this extension are described in
   Section 7.

   The received DNSSEC chain could contain DNS RRs that are not related
   to the TLSA verification of the intended DNS name.  If such an
   unrelated RR is not DNSSEC signed, it MUST be discarded.  If the
   unrelated RRset is DNSSEC signed, the TLS client MAY decide to add
   these RRsets and their DNSSEC signatures to its cache.  It MAY even
   pass this data to the local system resolver for caching outside the
   application.  However, care must be taken because caching these
   records could be used for timing and caching attacks to de-anonymize
   the TLS client or its user.  A TLS client that wants to present the
   strongest anonymity protection to their users MUST refrain from using
   and caching all unrelated RRs.

12.  IANA Considerations

   IANA has made the following assignment in the "TLS ExtensionType
   Values" registry:

      +=======+================+=========+=============+===========+
      | Value | Extension Name | TLS 1.3 | Recommended | Reference |
      +=======+================+=========+=============+===========+
      |    59 | dnssec_chain   | CH      | No          | RFC 9102  |
      +-------+----------------+---------+-------------+-----------+

                                 Table 1

13.  References

13.1.  Normative References

   [RFC1035]  Mockapetris, P., "Domain names - implementation and
              specification", STD 13, RFC 1035, DOI 10.17487/RFC1035,
              November 1987, <https://www.rfc-editor.org/info/rfc1035>.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC4033]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "DNS Security Introduction and Requirements",
              RFC 4033, DOI 10.17487/RFC4033, March 2005,
              <https://www.rfc-editor.org/info/rfc4033>.

   [RFC4034]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "Resource Records for the DNS Security Extensions",
              RFC 4034, DOI 10.17487/RFC4034, March 2005,
              <https://www.rfc-editor.org/info/rfc4034>.

   [RFC4035]  Arends, R., Austein, R., Larson, M., Massey, D., and S.
              Rose, "Protocol Modifications for the DNS Security
              Extensions", RFC 4035, DOI 10.17487/RFC4035, March 2005,
              <https://www.rfc-editor.org/info/rfc4035>.

   [RFC5155]  Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS
              Security (DNSSEC) Hashed Authenticated Denial of
              Existence", RFC 5155, DOI 10.17487/RFC5155, March 2008,
              <https://www.rfc-editor.org/info/rfc5155>.

   [RFC5246]  Dierks, T. and E. Rescorla, "The Transport Layer Security
              (TLS) Protocol Version 1.2", RFC 5246,
              DOI 10.17487/RFC5246, August 2008,
              <https://www.rfc-editor.org/info/rfc5246>.

   [RFC6066]  Eastlake 3rd, D., "Transport Layer Security (TLS)
              Extensions: Extension Definitions", RFC 6066,
              DOI 10.17487/RFC6066, January 2011,
              <https://www.rfc-editor.org/info/rfc6066>.

   [RFC6698]  Hoffman, P. and J. Schlyter, "The DNS-Based Authentication
              of Named Entities (DANE) Transport Layer Security (TLS)
              Protocol: TLSA", RFC 6698, DOI 10.17487/RFC6698, August
              2012, <https://www.rfc-editor.org/info/rfc6698>.

   [RFC7218]  Gudmundsson, O., "Adding Acronyms to Simplify
              Conversations about DNS-Based Authentication of Named
              Entities (DANE)", RFC 7218, DOI 10.17487/RFC7218, April
              2014, <https://www.rfc-editor.org/info/rfc7218>.

   [RFC7671]  Dukhovni, V. and W. Hardaker, "The DNS-Based
              Authentication of Named Entities (DANE) Protocol: Updates
              and Operational Guidance", RFC 7671, DOI 10.17487/RFC7671,
              October 2015, <https://www.rfc-editor.org/info/rfc7671>.

   [RFC7858]  Hu, Z., Zhu, L., Heidemann, J., Mankin, A., Wessels, D.,
              and P. Hoffman, "Specification for DNS over Transport
              Layer Security (TLS)", RFC 7858, DOI 10.17487/RFC7858, May
              2016, <https://www.rfc-editor.org/info/rfc7858>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

   [RFC8310]  Dickinson, S., Gillmor, D., and T. Reddy, "Usage Profiles
              for DNS over TLS and DNS over DTLS", RFC 8310,
              DOI 10.17487/RFC8310, March 2018,
              <https://www.rfc-editor.org/info/rfc8310>.

   [RFC8446]  Rescorla, E., "The Transport Layer Security (TLS) Protocol
              Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
              <https://www.rfc-editor.org/info/rfc8446>.

13.2.  Informative References

   [DANE-UKS] Barnes, R., Thomson, M., and E. Rescorla, "Unknown Key-
              Share Attacks on DNS-Based Authentications of Named
              Entities (DANE)", Work in Progress, Internet-Draft, draft-
              barnes-dane-uks-00, 9 October 2016,
              <https://datatracker.ietf.org/doc/html/draft-barnes-dane-
              uks-00>.

   [DISCOVERY]
              Gorjon, X. and W. Toorop, "Discovery method for a DNSSEC
              validating stub resolver", 14 July 2015,
              <https://www.nlnetlabs.nl/downloads/publications/
              os3-2015-rp2-xavier-torrent-gorjon.pdf>.

   [DNSOP-SVCB-HTTPS]
              Schwartz, B., Bishop, M., and E. Nygren, "Service Binding
              and Parameter Specification via the DNS (DNS SVCB and
              HTTPS RRs)", Work in Progress, Internet-Draft, draft-ietf-
              dnsop-svcb-https-07, 16 June 2021,
              <https://datatracker.ietf.org/doc/html/draft-ietf-dnsop-
              svcb-https-07>.

   [RFC5011]  StJohns, M., "Automated Updates of DNS Security (DNSSEC)
              Trust Anchors", STD 74, RFC 5011, DOI 10.17487/RFC5011,
              September 2007, <https://www.rfc-editor.org/info/rfc5011>.

   [RFC5905]  Mills, D., Martin, J., Ed., Burbank, J., and W. Kasch,
              "Network Time Protocol Version 4: Protocol and Algorithms
              Specification", RFC 5905, DOI 10.17487/RFC5905, June 2010,
              <https://www.rfc-editor.org/info/rfc5905>.

   [RFC7250]  Wouters, P., Ed., Tschofenig, H., Ed., Gilmore, J.,
              Weiler, S., and T. Kivinen, "Using Raw Public Keys in
              Transport Layer Security (TLS) and Datagram Transport
              Layer Security (DTLS)", RFC 7250, DOI 10.17487/RFC7250,
              June 2014, <https://www.rfc-editor.org/info/rfc7250>.

   [RFC7901]  Wouters, P., "CHAIN Query Requests in DNS", RFC 7901,
              DOI 10.17487/RFC7901, June 2016,
              <https://www.rfc-editor.org/info/rfc7901>.

   [SERIALIZECHAIN]
              Langley, A., "Serializing DNS Records with DNSSEC
              Authentication", Work in Progress, Internet-Draft, draft-
              agl-dane-serializechain-01, 1 July 2011,
              <https://datatracker.ietf.org/doc/html/draft-agl-dane-
              serializechain-01>.

Appendix A.  Test Vectors

   The test vectors in this appendix are representations of the content
   of the "opaque AuthenticationChain" field in DNS presentation format
   and, except for the "extension_data" in Appendix A.1, do not contain
   the "uint16 ExtSupportLifetime" field.

   For brevity and reproducibility, all DNS zones involved with the test
   vectors are signed using keys with algorithm 13 (ECDSA Curve P-256
   with SHA-256).

   To reflect operational practice, different zones in the examples are
   in different phases of rolling their signing keys:

   *  All zones use a Key Signing Key (KSK) and Zone Signing Key (ZSK),
      except for the "example.com" and "example.net" zones, which use a
      Combined Signing Key (CSK).

   *  The root and org zones are rolling their ZSKs.

   *  The com and org zones are rolling their KSKs.

   The test vectors are DNSSEC valid in the same period as the
   certificate is valid, which is between November 28, 2018 and December
   2, 2020 with the following root trust anchor:

   .  IN  DS  ( 47005 13 2 2eb6e9f2480126691594d649a5a613de3052e37861634
           641bb568746f2ffc4d4 )

   The test vectors will authenticate the certificate used with
   "https://example.com/", "https://example.net/", and
   "https://example.org/" at the time of writing:

   -----BEGIN CERTIFICATE-----
   MIIHQDCCBiigAwIBAgIQD9B43Ujxor1NDyupa2A4/jANBgkqhkiG9w0BAQsFADBN
   MQswCQYDVQQGEwJVUzEVMBMGA1UEChMMRGlnaUNlcnQgSW5jMScwJQYDVQQDEx5E
   aWdpQ2VydCBTSEEyIFNlY3VyZSBTZXJ2ZXIgQ0EwHhcNMTgxMTI4MDAwMDAwWhcN
   MjAxMjAyMTIwMDAwWjCBpTELMAkGA1UEBhMCVVMxEzARBgNVBAgTCkNhbGlmb3Ju
   aWExFDASBgNVBAcTC0xvcyBBbmdlbGVzMTwwOgYDVQQKEzNJbnRlcm5ldCBDb3Jw
   b3JhdGlvbiBmb3IgQXNzaWduZWQgTmFtZXMgYW5kIE51bWJlcnMxEzARBgNVBAsT
   ClRlY2hub2xvZ3kxGDAWBgNVBAMTD3d3dy5leGFtcGxlLm9yZzCCASIwDQYJKoZI
   hvcNAQEBBQADggEPADCCAQoCggEBANDwEnSgliByCGUZElpdStA6jGaPoCkrp9vV
   rAzPpXGSFUIVsAeSdjF11yeOTVBqddF7U14nqu3rpGA68o5FGGtFM1yFEaogEv5g
   rJ1MRY/d0w4+dw8JwoVlNMci+3QTuUKf9yH28JxEdG3J37Mfj2C3cREGkGNBnY80
   eyRJRqzy8I0LSPTTkhr3okXuzOXXg38ugr1x3SgZWDNuEaE6oGpyYJIBWZ9jF3pJ
   QnucP9vTBejMh374qvyd0QVQq3WxHrogy4nUbWw3gihMxT98wRD1oKVma1NTydvt
   hcNtBfhkp8kO64/hxLHrLWgOFT/l4tz8IWQt7mkrBHjbd2XLVPkCAwEAAaOCA8Ew
   ggO9MB8GA1UdIwQYMBaAFA+AYRyCMWHVLyjnjUY4tCzhxtniMB0GA1UdDgQWBBRm
   mGIC4AmRp9njNvt2xrC/oW2nvjCBgQYDVR0RBHoweIIPd3d3LmV4YW1wbGUub3Jn
   ggtleGFtcGxlLmNvbYILZXhhbXBsZS5lZHWCC2V4YW1wbGUubmV0ggtleGFtcGxl
   Lm9yZ4IPd3d3LmV4YW1wbGUuY29tgg93d3cuZXhhbXBsZS5lZHWCD3d3dy5leGFt
   cGxlLm5ldDAOBgNVHQ8BAf8EBAMCBaAwHQYDVR0lBBYwFAYIKwYBBQUHAwEGCCsG
   AQUFBwMCMGsGA1UdHwRkMGIwL6AtoCuGKWh0dHA6Ly9jcmwzLmRpZ2ljZXJ0LmNv
   bS9zc2NhLXNoYTItZzYuY3JsMC+gLaArhilodHRwOi8vY3JsNC5kaWdpY2VydC5j
   b20vc3NjYS1zaGEyLWc2LmNybDBMBgNVHSAERTBDMDcGCWCGSAGG/WwBATAqMCgG
   CCsGAQUFBwIBFhxodHRwczovL3d3dy5kaWdpY2VydC5jb20vQ1BTMAgGBmeBDAEC
   AjB8BggrBgEFBQcBAQRwMG4wJAYIKwYBBQUHMAGGGGh0dHA6Ly9vY3NwLmRpZ2lj
   ZXJ0LmNvbTBGBggrBgEFBQcwAoY6aHR0cDovL2NhY2VydHMuZGlnaWNlcnQuY29t
   L0RpZ2lDZXJ0U0hBMlNlY3VyZVNlcnZlckNBLmNydDAMBgNVHRMBAf8EAjAAMIIB
   fwYKKwYBBAHWeQIEAgSCAW8EggFrAWkAdwCkuQmQtBhYFIe7E6LMZ3AKPDWYBPkb
   37jjd80OyA3cEAAAAWdcMZVGAAAEAwBIMEYCIQCEZIG3IR36Gkj1dq5L6EaGVycX
   sHvpO7dKV0JsooTEbAIhALuTtf4wxGTkFkx8blhTV+7sf6pFT78ORo7+cP39jkJC
   AHYAh3W/51l8+IxDmV+9827/Vo1HVjb/SrVgwbTq/16ggw8AAAFnXDGWFQAABAMA
   RzBFAiBvqnfSHKeUwGMtLrOG3UGLQIoaL3+uZsGTX3MfSJNQEQIhANL5nUiGBR6g
   l0QlCzzqzvorGXyB/yd7nttYttzo8EpOAHYAb1N2rDHwMRnYmQCkURX/dxUcEdkC
   wQApBo2yCJo32RMAAAFnXDGWnAAABAMARzBFAiEA5Hn7Q4SOyqHkT+kDsHq7ku7z
   RDuM7P4UDX2ft2Mpny0CIE13WtxJAUr0aASFYZ/XjSAMMfrB0/RxClvWVss9LHKM
   MA0GCSqGSIb3DQEBCwUAA4IBAQBzcIXvQEGnakPVeJx7VUjmvGuZhrr7DQOLeP4R
   8CmgDM1pFAvGBHiyzvCH1QGdxFl6cf7wbp7BoLCRLR/qPVXFMwUMzcE1GLBqaGZM
   v1Yh2lvZSLmMNSGRXdx113pGLCInpm/TOhfrvr0TxRImc8BdozWJavsn1N2qdHQu
   N+UBO6bQMLCD0KHEdSGFsuX6ZwAworxTg02/1qiDu7zW7RyzHvFYA4IAjpzvkPIa
   X6KjBtpdvp/aXabmL95YgBjT8WJ7pqOfrqhpcmOBZa6Cg6O1l4qbIFH/Gj9hQB5I
   0Gs4+eH6F9h3SojmPTYkT+8KuZ9w84Mn+M8qBXUQoYoKgIjN
   -----END CERTIFICATE-----

A.1.  "_443._tcp.www.example.com"

   _443._tcp.www.example.com.  3600  IN  TLSA  ( 3 1 1
           8bd1da95272f7fa4ffb24137fc0ed03aae67e5c4d8b3c50734e1050a7920b
           922 )
   _443._tcp.www.example.com.  3600  IN  RRSIG  ( TLSA 13 5 3600
           20201202000000 20181128000000 1870 example.com.
           rqY69NnTf4CN3GBGQjKEJCLAMsRkUrXe0JW8IqDb5rQHHzxNqqPeEoi+2vI6S
           z2BhaswpGLVVuoijuVdzxYjmw== )
   example.com.  3600  IN  DNSKEY  ( 257 3 13
           JnA1XgyJTZz+psWvbrfUWLV6ULqIJyUS2CQdhUH9VK35bslWeJpRzrlxCUs7s
           /TsSfZMaGWVvlsuieh5nHcXzA== ) ; Key ID = 1870
   example.com.  3600  IN  RRSIG  ( DNSKEY 13 2 3600
           20201202000000 20181128000000 1870 example.com.
           nYisnu/26Sw1qmGuREa9o/fLgYuA4oNPt4+6PMBZoN0MS8Gjtli9NVRYeSIzt
           QHPGSpvRxTUC4tZi62z1UgGDw== )
   example.com.  172800  IN  DS  ( 1870 13 2 e9b533a049798e900b5c29c90cd
          25a986e8a44f319ac3cd302bafc08f5b81e16)
   example.com.  172800  IN  RRSIG  ( DS 13 2 172800
           20201202000000 20181128000000 34327 com.
           sEAKvX4H6pJfN8nKcclB1NRcRSPOztx8omr4fCSHu6lp+uESP/Le4iF2sKukO
           J1hhWSB6jgubEVl17rGNOA/YQ== )
   com.  172800  IN  DNSKEY  ( 256 3 13
           7IIE5Dol8jSMUqHTvOOiZapdEbQ9wqRxFi/zQcSdufUKLhpByvLpzSAQTqCWj
           3URIZ8L3Fa2gBLMOZUzZ1GQCw== ) ; Key ID = 34327
   com.  172800  IN  DNSKEY  ( 257 3 13
           RbkcO+96XZmnp8jYIuM4lryAp3egQjSmBaSoiA7H76Tm0RLHPNPUxlVk+nQ0f
           Ic3I8xfZDNw8Wa0Pe3/g2QA/w== ) ; Key ID = 18931
   com.  172800  IN  DNSKEY  ( 257 3 13
           szc7biLo5J4OHlkan1vZrF4aD4YYf+NHA/GAqdNslY9xxK9Izg68XHkqck4Rt
           DiVk37lNAQmgSlHbrGu0yOTkA== ) ; Key ID = 28809
   com.  172800  IN  RRSIG  ( DNSKEY 13 1 172800 20201202000000
           20181128000000 18931 com.
           LJ4p5ORS2ViILwTotSlWixElqRXHY5tOdIuHlPWTdBGPMq3y40QNr1V+ZOyA5
           7LFdPKpcvb8BvhM+GqKWGBEsg== )
   com.  172800  IN  RRSIG  ( DNSKEY 13 1 172800 20201202000000
           20181128000000 28809 com.
           sO+4X2N21yS6x8+dBVBzbRo9+55MM8n7+RUvdBuxRFVh6JaBlqDOC5LLkl7Ev
           mDXqz6KEhhQjT+aQWDt6WFHlA== )
   com.  86400  IN  DS  ( 18931 13 2 20f7a9db42d0e2042fbbb9f9ea015941202
           f9eabb94487e658c188e7bcb52115 )
   com.  86400  IN  DS  ( 28809 13 2 ad66b3276f796223aa45eda773e92c6d98e
           70643bbde681db342a9e5cf2bb380 )
   com.  86400  IN  RRSIG  ( DS 13 1 86400 20201202000000
           20181128000000 31918 .
           nDiDlBjXEE/6AudhC++Hui1ckPcuAnGbjEASNoxA3ZHjlXRzL050UzePko5Pb
           vBKTf6pk8JRCqnfzlo2QY+WXA== )
   .  86400  IN  DNSKEY  ( 256 3 13
           zKz+DCWkNA/vuheiVPcGqsH40U84KZAlrMRIyozj9WHzf8PsFp/oR8j8vmjjW
           P98cbte4d8NvlGLxzbUzo3+FA== ) ; Key ID = 31918
   .  86400  IN  DNSKEY  ( 256 3 13
           8wMZZ4lzHdyKZ4fv8kys/t3QMlgvEadbsbyqWrMhwddSXCZYGRrsAbPpireRW
           xbVcd1VtOrlFBcRDMTN0R0XEQ== ) ; Key ID = 2635
   .  86400  IN  DNSKEY  ( 257 3 13
           yvX+VNTUjxZiGvtr060hVbrPV9H6rVusQtF9lIxCFzbZOJxMQBFmbqlc8Xclv
           Q+gDOXnFOTsgs/frMmxyGOtRg== ) ; Key ID = 47005
   .  86400  IN  RRSIG  ( DNSKEY 13 0 86400 20201202000000
           20181128000000 47005 .
           0EPW1ca+N/ZhZPKla77STG734cTeIOjUwq7eW0HsnOfudWmnCEVeco2wLLq9m
           nBT1dtNjIczvLG9pQTnOKUsHQ== )

   A hex dump of the "extension_data" of the server's "dnssec_chain"
   extension representation of this with an ExtSupportLifetime value of
   0 is:

   0000:  00 00 04 5f 34 34 33 04  5f 74 63 70 03 77 77 77
   0010:  07 65 78 61 6d 70 6c 65  03 63 6f 6d 00 00 34 00
   0020:  01 00 00 0e 10 00 23 03  01 01 8b d1 da 95 27 2f
   0030:  7f a4 ff b2 41 37 fc 0e  d0 3a ae 67 e5 c4 d8 b3
   0040:  c5 07 34 e1 05 0a 79 20  b9 22 04 5f 34 34 33 04
   0050:  5f 74 63 70 03 77 77 77  07 65 78 61 6d 70 6c 65
   0060:  03 63 6f 6d 00 00 2e 00  01 00 00 0e 10 00 5f 00
   0070:  34 0d 05 00 00 0e 10 5f  c6 d9 00 5b fd da 80 07
   0080:  4e 07 65 78 61 6d 70 6c  65 03 63 6f 6d 00 ce 1d
   0090:  3a de b7 dc 7c ee 65 6d  61 cf b4 72 c5 97 7c 8c
   00a0:  9c ae ae 9b 76 51 55 c5  18 fb 10 7b 6a 1f e0 35
   00b0:  5f ba af 75 3c 19 28 32  fa 62 1f a7 3a 8b 85 ed
   00c0:  79 d3 74 11 73 87 59 8f  cc 81 2e 1e f3 fb 07 65
   00d0:  78 61 6d 70 6c 65 03 63  6f 6d 00 00 30 00 01 00
   00e0:  00 0e 10 00 44 01 01 03  0d 26 70 35 5e 0c 89 4d
   00f0:  9c fe a6 c5 af 6e b7 d4  58 b5 7a 50 ba 88 27 25
   0100:  12 d8 24 1d 85 41 fd 54  ad f9 6e c9 56 78 9a 51
   0110:  ce b9 71 09 4b 3b b3 f4  ec 49 f6 4c 68 65 95 be
   0120:  5b 2e 89 e8 79 9c 77 17  cc 07 65 78 61 6d 70 6c
   0130:  65 03 63 6f 6d 00 00 2e  00 01 00 00 0e 10 00 5f
   0140:  00 30 0d 02 00 00 0e 10  5f c6 d9 00 5b fd da 80
   0150:  07 4e 07 65 78 61 6d 70  6c 65 03 63 6f 6d 00 46
   0160:  28 38 30 75 b8 e3 4b 74  3a 20 9b 27 ae 14 8d 11
   0170:  0d 4e 1a 24 61 38 a9 10  83 24 9c b4 a1 2a 2d 9b
   0180:  c4 c2 d7 ab 5e b3 af b9  f5 d1 03 7e 4d 5d a8 33
   0190:  9c 16 2a 92 98 e9 be 18  07 41 a8 ca 74 ac cc 07
   01a0:  65 78 61 6d 70 6c 65 03  63 6f 6d 00 00 2b 00 01
   01b0:  00 02 a3 00 00 24 07 4e  0d 02 e9 b5 33 a0 49 79
   01c0:  8e 90 0b 5c 29 c9 0c d2  5a 98 6e 8a 44 f3 19 ac
   01d0:  3c d3 02 ba fc 08 f5 b8  1e 16 07 65 78 61 6d 70
   01e0:  6c 65 03 63 6f 6d 00 00  2e 00 01 00 02 a3 00 00
   01f0:  57 00 2b 0d 02 00 02 a3  00 5f c6 d9 00 5b fd da
   0200:  80 86 17 03 63 6f 6d 00  a2 03 e7 04 a6 fa cb eb
   0210:  13 fc 93 84 fd d6 de 6b  50 de 56 59 27 1f 38 ce
   0220:  81 49 86 84 e6 36 31 72  d4 7e 23 19 fd b4 a2 2a
   0230:  58 a2 31 ed c2 f1 ff 4f  b2 81 1a 18 07 be 72 cb
   0240:  52 41 aa 26 fd ae e0 39  03 63 6f 6d 00 00 30 00
   0250:  01 00 02 a3 00 00 44 01  00 03 0d ec 82 04 e4 3a
   0260:  25 f2 34 8c 52 a1 d3 bc  e3 a2 65 aa 5d 11 b4 3d
   0270:  c2 a4 71 16 2f f3 41 c4  9d b9 f5 0a 2e 1a 41 ca
   0280:  f2 e9 cd 20 10 4e a0 96  8f 75 11 21 9f 0b dc 56
   0290:  b6 80 12 cc 39 95 33 67  51 90 0b 03 63 6f 6d 00
   02a0:  00 30 00 01 00 02 a3 00  00 44 01 01 03 0d 45 b9
   02b0:  1c 3b ef 7a 5d 99 a7 a7  c8 d8 22 e3 38 96 bc 80
   02c0:  a7 77 a0 42 34 a6 05 a4  a8 88 0e c7 ef a4 e6 d1
   02d0:  12 c7 3c d3 d4 c6 55 64  fa 74 34 7c 87 37 23 cc
   02e0:  5f 64 33 70 f1 66 b4 3d  ed ff 83 64 00 ff 03 63
   02f0:  6f 6d 00 00 30 00 01 00  02 a3 00 00 44 01 01 03
   0300:  0d b3 37 3b 6e 22 e8 e4  9e 0e 1e 59 1a 9f 5b d9
   0310:  ac 5e 1a 0f 86 18 7f e3  47 03 f1 80 a9 d3 6c 95
   0320:  8f 71 c4 af 48 ce 0e bc  5c 79 2a 72 4e 11 b4 38
   0330:  95 93 7e e5 34 04 26 81  29 47 6e b1 ae d3 23 93
   0340:  90 03 63 6f 6d 00 00 2e  00 01 00 02 a3 00 00 57
   0350:  00 30 0d 01 00 02 a3 00  5f c6 d9 00 5b fd da 80
   0360:  49 f3 03 63 6f 6d 00 18  a9 48 eb 23 d4 4f 80 ab
   0370:  c9 92 38 fc b4 3c 5a 18  de be 57 00 4f 73 43 59
   0380:  3f 6d eb 6e d7 1e 04 65  4a 43 3f 7a a1 97 21 30
   0390:  d9 bd 92 1c 73 dc f6 3f  cf 66 5f 2f 05 a0 aa eb
   03a0:  af b0 59 dc 12 c9 65 03  63 6f 6d 00 00 2e 00 01
   03b0:  00 02 a3 00 00 57 00 30  0d 01 00 02 a3 00 5f c6
   03c0:  d9 00 5b fd da 80 70 89  03 63 6f 6d 00 61 70 e6
   03d0:  95 9b d9 ed 6e 57 58 37  b6 f5 80 bd 99 db d2 4a
   03e0:  44 68 2b 0a 35 96 26 a2  46 b1 81 2f 5f 90 96 b7
   03f0:  5e 15 7e 77 84 8f 06 8a  e0 08 5e 1a 60 9f c1 92
   0400:  98 c3 3b 73 68 63 fb cc  d4 d8 1f 5e b2 03 63 6f
   0410:  6d 00 00 2b 00 01 00 01  51 80 00 24 49 f3 0d 02
   0420:  20 f7 a9 db 42 d0 e2 04  2f bb b9 f9 ea 01 59 41
   0430:  20 2f 9e ab b9 44 87 e6  58 c1 88 e7 bc b5 21 15
   0440:  03 63 6f 6d 00 00 2b 00  01 00 01 51 80 00 24 70
   0450:  89 0d 02 ad 66 b3 27 6f  79 62 23 aa 45 ed a7 73
   0460:  e9 2c 6d 98 e7 06 43 bb  de 68 1d b3 42 a9 e5 cf
   0470:  2b b3 80 03 63 6f 6d 00  00 2e 00 01 00 01 51 80
   0480:  00 53 00 2b 0d 01 00 01  51 80 5f c6 d9 00 5b fd
   0490:  da 80 7c ae 00 12 2e 27  6d 45 d9 e9 81 6f 79 22
   04a0:  ad 6e a2 e7 3e 82 d2 6f  ce 0a 4b 71 86 25 f3 14
   04b0:  53 1a c9 2f 8a e8 24 18  df 9b 89 8f 98 9d 32 e8
   04c0:  0b c4 de ab a7 c4 a7 c8  f1 72 ad b5 7c ed 7f b5
   04d0:  e7 7a 78 4b 07 00 00 30  00 01 00 01 51 80 00 44
   04e0:  01 00 03 0d cc ac fe 0c  25 a4 34 0f ef ba 17 a2
   04f0:  54 f7 06 aa c1 f8 d1 4f  38 29 90 25 ac c4 48 ca
   0500:  8c e3 f5 61 f3 7f c3 ec  16 9f e8 47 c8 fc be 68
   0510:  e3 58 ff 7c 71 bb 5e e1  df 0d be 51 8b c7 36 d4
   0520:  ce 8d fe 14 00 00 30 00  01 00 01 51 80 00 44 01
   0530:  00 03 0d f3 03 19 67 89  73 1d dc 8a 67 87 ef f2
   0540:  4c ac fe dd d0 32 58 2f  11 a7 5b b1 bc aa 5a b3
   0550:  21 c1 d7 52 5c 26 58 19  1a ec 01 b3 e9 8a b7 91
   0560:  5b 16 d5 71 dd 55 b4 ea  e5 14 17 11 0c c4 cd d1
   0570:  1d 17 11 00 00 30 00 01  00 01 51 80 00 44 01 01
   0580:  03 0d ca f5 fe 54 d4 d4  8f 16 62 1a fb 6b d3 ad
   0590:  21 55 ba cf 57 d1 fa ad  5b ac 42 d1 7d 94 8c 42
   05a0:  17 36 d9 38 9c 4c 40 11  66 6e a9 5c f1 77 25 bd
   05b0:  0f a0 0c e5 e7 14 e4 ec  82 cf df ac c9 b1 c8 63
   05c0:  ad 46 00 00 2e 00 01 00  01 51 80 00 53 00 30 0d
   05d0:  00 00 01 51 80 5f c6 d9  00 5b fd da 80 b7 9d 00
   05e0:  de 7a 67 40 ee ec ba 4b  da 1e 5c 2d d4 89 9b 2c
   05f0:  96 58 93 f3 78 6c e7 47  f4 1e 50 d9 de 8c 0a 72
   0600:  df 82 56 0d fb 48 d7 14  de 32 83 ae 99 a4 9c 0f
   0610:  cb 50 d3 aa ad b1 a3 fc  62 ee 3a 8a 09 88 b6 be

A.2.  "_25._tcp.example.com" NSEC Wildcard

   _25._tcp.example.com.  3600  IN  TLSA  ( 3 1 1
           8bd1da95272f7fa4ffb24137fc0ed03aae67e5c4d8b3c50734e1050a7920b
           922 )
   _25._tcp.example.com.  3600  IN  RRSIG  ( TLSA 13 3 3600
           20201202000000 20181128000000 1870 example.com.
           BZawXvte5SyF8hnXviKDWqll5E2v+RMXqaSE+NOcAMlZOrSMUkfyPqvkv53K2
           rfL4DFP8rO3VMgI0v+ogrox0w== )
   *._tcp.example.com.  3600  IN  NSEC  ( smtp.example.com. RRSIG
           NSEC TLSA )
   *._tcp.example.com.  3600  IN  RRSIG  ( NSEC 13 3 3600
           20201202000000 20181128000000 1870 example.com.
           K6u8KrR8ca5bjtbce3w8yjMXr9vw12225lAwyIHpxptY43OMLCUCenwpYW5qd
           mpFvAacqj4+tSkKiN279SI9pA== )
   example.com.  3600  IN  DNSKEY  ( 257 3 13
           JnA1XgyJTZz+psWvbrfUWLV6ULqIJyUS2CQdhUH9VK35bslWeJpRzrlxCUs7s
           /TsSfZMaGWVvlsuieh5nHcXzA== ) ; Key ID = 1870
   example.com.  3600  IN  RRSIG  ( DNSKEY 13 2 3600
           20201202000000 20181128000000 1870 example.com.
           nYisnu/26Sw1qmGuREa9o/fLgYuA4oNPt4+6PMBZoN0MS8Gjtli9NVRYeSIzt
           QHPGSpvRxTUC4tZi62z1UgGDw== )
   example.com.  172800  IN  DS  ( 1870 13 2 e9b533a049798e900b5c29c90cd
           25a986e8a44f319ac3cd302bafc08f5b81e16 )
   example.com.  172800  IN  RRSIG  ( DS 13 2 172800
           20201202000000 20181128000000 34327 com.
           sEAKvX4H6pJfN8nKcclB1NRcRSPOztx8omr4fCSHu6lp+uESP/Le4iF2sKukO
           J1hhWSB6jgubEVl17rGNOA/YQ== )
   com.  172800  IN  DNSKEY  ( 256 3 13
           7IIE5Dol8jSMUqHTvOOiZapdEbQ9wqRxFi/zQcSdufUKLhpByvLpzSAQTqCWj
           3URIZ8L3Fa2gBLMOZUzZ1GQCw== ) ; Key ID = 34327
   com.  172800  IN  DNSKEY  ( 257 3 13
           RbkcO+96XZmnp8jYIuM4lryAp3egQjSmBaSoiA7H76Tm0RLHPNPUxlVk+nQ0f
           Ic3I8xfZDNw8Wa0Pe3/g2QA/w== ) ; Key ID = 18931
   com.  172800  IN  DNSKEY  ( 257 3 13
           szc7biLo5J4OHlkan1vZrF4aD4YYf+NHA/GAqdNslY9xxK9Izg68XHkqck4Rt
           DiVk37lNAQmgSlHbrGu0yOTkA== ) ; Key ID = 28809
   com.  172800  IN  RRSIG  ( DNSKEY 13 1 172800 20201202000000
           20181128000000 18931 com.
           LJ4p5ORS2ViILwTotSlWixElqRXHY5tOdIuHlPWTdBGPMq3y40QNr1V+ZOyA5
           7LFdPKpcvb8BvhM+GqKWGBEsg== )
   com.  172800  IN  RRSIG  ( DNSKEY 13 1 172800 20201202000000
           20181128000000 28809 com.
           sO+4X2N21yS6x8+dBVBzbRo9+55MM8n7+RUvdBuxRFVh6JaBlqDOC5LLkl7Ev
           mDXqz6KEhhQjT+aQWDt6WFHlA== )
   com.  86400  IN  DS  ( 18931 13 2 20f7a9db42d0e2042fbbb9f9ea015941202
           f9eabb94487e658c188e7bcb52115 )
   com.  86400  IN  DS  ( 28809 13 2 ad66b3276f796223aa45eda773e92c6d98e
           70643bbde681db342a9e5cf2bb380 )
   com.  86400  IN  RRSIG  ( DS 13 1 86400 20201202000000
           20181128000000 31918 .
           nDiDlBjXEE/6AudhC++Hui1ckPcuAnGbjEASNoxA3ZHjlXRzL050UzePko5Pb
           vBKTf6pk8JRCqnfzlo2QY+WXA== )
   .  86400  IN  DNSKEY  ( 256 3 13
           zKz+DCWkNA/vuheiVPcGqsH40U84KZAlrMRIyozj9WHzf8PsFp/oR8j8vmjjW
           P98cbte4d8NvlGLxzbUzo3+FA== ) ; Key ID = 31918
   .  86400  IN  DNSKEY  ( 256 3 13
           8wMZZ4lzHdyKZ4fv8kys/t3QMlgvEadbsbyqWrMhwddSXCZYGRrsAbPpireRW
           xbVcd1VtOrlFBcRDMTN0R0XEQ== ) ; Key ID = 2635
   .  86400  IN  DNSKEY  ( 257 3 13
           yvX+VNTUjxZiGvtr060hVbrPV9H6rVusQtF9lIxCFzbZOJxMQBFmbqlc8Xclv
           Q+gDOXnFOTsgs/frMmxyGOtRg== ) ; Key ID = 47005
   .  86400  IN  RRSIG  ( DNSKEY 13 0 86400 20201202000000
           20181128000000 47005 .
           0EPW1ca+N/ZhZPKla77STG734cTeIOjUwq7eW0HsnOfudWmnCEVeco2wLLq9m
           nBT1dtNjIczvLG9pQTnOKUsHQ== )

A.3.  "_25._tcp.example.org" NSEC3 Wildcard

   _25._tcp.example.org.  3600  IN  TLSA  ( 3 1 1
           8bd1da95272f7fa4ffb24137fc0ed03aae67e5c4d8b3c50734e1050a7920b
           922 )
   _25._tcp.example.org.  3600  IN  RRSIG  ( TLSA 13 3 3600
           20201202000000 20181128000000 56566 example.org.
           lNp6th/CJel5WsYlLsLadcQ/YdSTJAIOttzYKnNkNzeZ0jxtDyEP818Q1R4lL
           cYzJ7vCvqb9gFCiCJjK2gAamw== )
   dlm7rss9pejqnh0ev6h7k1ikqqcl5mae.example.org.  3600  IN  NSEC3  (
           1 0 1 - t6lf7uuoi0qofq0nvdjroavo46pp20im RRSIG TLSA )
   dlm7rss9pejqnh0ev6h7k1ikqqcl5mae.example.org.  3600  IN  RRSIG  (
           NSEC3 13 3 3600 20201202000000 20181128000000 56566
           example.org.
           guUyy9LIZlYb0FZttAdYJGrFNKpKu91Tm+dPOz98rnpwIlwwvLifXIvIl90nE
           X38cWzEQOpreJu3t4WAfPsxdg== )
   example.org.  3600  IN  DNSKEY  ( 256 3 13
           NrbL6utGqIW1wrhhjeexdA6bMdD1lC1hj0Fnpevaa1AMyY2uy83TmoGnR996N
           UR5TlG4Zh+YPbbmUIixe4nS3w== ) ; Key ID = 56566
   example.org.  3600  IN  DNSKEY  ( 257 3 13
           uspaqp17jsMTX6AWVgmbog/3Sttz+9ANFUWLn6qKUHr0BOqRuChQWj8jyYUUr
           Wy9txxesNQ9MkO4LUrFght1LQ== ) ; Key ID = 44384
   example.org.  3600  IN  RRSIG  ( DNSKEY 13 2 3600
           20201202000000 20181128000000 44384 example.org.
           ttse9pYp9PSu0pJ+TOpIVFLWJ6NKOMWZX4Q/SlU6ZfaiKQc0Bg7Tut9+wPunk
           6OPPvyHjVXMAsvk0tqV0B+/ag== )
   example.org.  86400  IN  DS  ( 44384 13 2 ec307e2efc8f0117ed96ab48a51
           3c8003e1d9121f1ff11a08b4cdd348d090aa6 )
   example.org.  86400  IN  RRSIG  ( DS 13 2 86400 20201202000000
           20181128000000 9523 org.
           m86Xz0CEa2sWG40a0bS2kqLKPmIlyiVyDeoWXAq3djeGiPaikLuKORNzWXu62
           clpAfvZHx59Ackst4X+zXYpUA== )
   org.  86400  IN  DNSKEY  ( 256 3 13
           fuLp60znhSSEr9HowILpTpyLKQdM6ixcgkTE0gqVdsLx+DSNHSc69o6fLWC0e
           HfWx7kzlBBoJB0vLrvsJtXJ6g== ) ; Key ID = 47417
   org.  86400  IN  DNSKEY  ( 256 3 13
           zTHbb7JM627Bjr8CGOySUarsic91xZU3vvLJ5RjVix9YH6+iwpBXb6qfHyQHy
           mlMiAAoaoXh7BUkEBVgDVN8sQ== ) ; Key ID = 9523
   org.  86400  IN  DNSKEY  ( 257 3 13
           Uf24EyNt51DMcLV+dHPInhSpmjPnqAQNUTouU+SGLu+lFRRlBetgw1bJUZNI6
           Dlger0VJTm0QuX/JVXcyGVGoQ== ) ; Key ID = 49352
   org.  86400  IN  DNSKEY  ( 257 3 13
           0SZfoe8Yx+eoaGgyAGEeJax/ZBV1AuG+/smcOgRm+F6doNlgc3lddcM1MbTvJ
           HTjK6Fvy8W6yZ+cAptn8sQheg== ) ; Key ID = 12651
   org.  86400  IN  RRSIG  ( DNSKEY 13 1 86400 20201202000000
           20181128000000 12651 org.
           Gq9wf+z3pasXXUwE210jYc0LhJnMAhcwXydnvkHtCVY6/0jUafHO4RksN84Zt
           us0pUgWngbT/OWXskdMYXZU4A== )
   org.  86400  IN  RRSIG  ( DNSKEY 13 1 86400 20201202000000
           20181128000000 49352 org.
           VGEkEMWBJ2IbOpm2Z56Qxu2NGPcVUDWCbYRyk+Qk1+HzGtyd2qPEKkpgMs/0p
           vZEMj1YXD+dIqb2nUK9PGBAXw== )
   org.  86400  IN  DS  ( 12651 13 2 3979a51f98bbf219fcaf4a4176e766dfa8f
           9db5c24a75743eb1e704b97a9fabc )
   org.  86400  IN  DS  ( 49352 13 2 03d11a1aa114abbb8f708c3c0ff0db765fe
           f4a2f18920db5f58710dd767c293b )
   org.  86400  IN  RRSIG  ( DS 13 1 86400 20201202000000
           20181128000000 31918 .
           adiFuP2UIulQw5Edsb/7WSPqr5nkRSTVXbZ2tkBeZRQcMjdCD3pyonWO5JPRV
           EemgaE357S4pX5D0tVZzeZJ6A== )
   .  86400  IN  DNSKEY  ( 256 3 13
           zKz+DCWkNA/vuheiVPcGqsH40U84KZAlrMRIyozj9WHzf8PsFp/oR8j8vmjjW
           P98cbte4d8NvlGLxzbUzo3+FA== ) ; Key ID = 31918
   .  86400  IN  DNSKEY  ( 256 3 13
           8wMZZ4lzHdyKZ4fv8kys/t3QMlgvEadbsbyqWrMhwddSXCZYGRrsAbPpireRW
           xbVcd1VtOrlFBcRDMTN0R0XEQ== ) ; Key ID = 2635
   .  86400  IN  DNSKEY  ( 257 3 13
           yvX+VNTUjxZiGvtr060hVbrPV9H6rVusQtF9lIxCFzbZOJxMQBFmbqlc8Xclv
           Q+gDOXnFOTsgs/frMmxyGOtRg== ) ; Key ID = 47005
   .  86400  IN  RRSIG  ( DNSKEY 13 0 86400 20201202000000
           20181128000000 47005 .
           0EPW1ca+N/ZhZPKla77STG734cTeIOjUwq7eW0HsnOfudWmnCEVeco2wLLq9m
           nBT1dtNjIczvLG9pQTnOKUsHQ== )

A.4.  "_443._tcp.www.example.org" CNAME

   _443._tcp.www.example.org.  3600  IN  CNAME  (
           dane311.example.org. )
   _443._tcp.www.example.org.  3600  IN  RRSIG  ( CNAME 13 5 3600
           20201202000000 20181128000000 56566 example.org.
           R0dUe6Rt4G+2ablrQH9Zw8j9NhBLMgNYTI5+H7nO8SNz5Nm8w0NZrXv3Qp7gx
           Qb/a90O696120NsYaZX2+ebBA== )
   dane311.example.org.  3600  IN  TLSA  ( 3 1 1
           8bd1da95272f7fa4ffb24137fc0ed03aae67e5c4d8b3c50734e1050a7920b
           922 )
   dane311.example.org.  3600  IN  RRSIG  ( TLSA 13 3 3600
           20201202000000 20181128000000 56566 example.org.
           f6TbTZTpu3h6MYpLkKQwWILAkYQ3EUY+Nsoa6any6yt+aeuunMUjw+IJB2QLm
           0x0PrD7m39JA3NUSkUp9riNNQ== )
   example.org.  3600  IN  DNSKEY  ( 256 3 13
           NrbL6utGqIW1wrhhjeexdA6bMdD1lC1hj0Fnpevaa1AMyY2uy83TmoGnR996N
           UR5TlG4Zh+YPbbmUIixe4nS3w== ) ; Key ID = 56566
   example.org.  3600  IN  DNSKEY  ( 257 3 13
           uspaqp17jsMTX6AWVgmbog/3Sttz+9ANFUWLn6qKUHr0BOqRuChQWj8jyYUUr
           Wy9txxesNQ9MkO4LUrFght1LQ== ) ; Key ID = 44384
   example.org.  3600  IN  RRSIG  ( DNSKEY 13 2 3600
           20201202000000 20181128000000 44384 example.org.
           ttse9pYp9PSu0pJ+TOpIVFLWJ6NKOMWZX4Q/SlU6ZfaiKQc0Bg7Tut9+wPunk
           6OPPvyHjVXMAsvk0tqV0B+/ag== )
   example.org.  86400  IN  DS  ( 44384 13 2 ec307e2efc8f0117ed96ab48a51
           3c8003e1d9121f1ff11a08b4cdd348d090aa6 )
   example.org.  86400  IN  RRSIG  ( DS 13 2 86400 20201202000000
           20181128000000 9523 org.
           m86Xz0CEa2sWG40a0bS2kqLKPmIlyiVyDeoWXAq3djeGiPaikLuKORNzWXu62
           clpAfvZHx59Ackst4X+zXYpUA== )
   org.  86400  IN  DNSKEY  ( 256 3 13
           fuLp60znhSSEr9HowILpTpyLKQdM6ixcgkTE0gqVdsLx+DSNHSc69o6fLWC0e
           HfWx7kzlBBoJB0vLrvsJtXJ6g== ) ; Key ID = 47417
   org.  86400  IN  DNSKEY  ( 256 3 13
           zTHbb7JM627Bjr8CGOySUarsic91xZU3vvLJ5RjVix9YH6+iwpBXb6qfHyQHy
           mlMiAAoaoXh7BUkEBVgDVN8sQ== ) ; Key ID = 9523
   org.  86400  IN  DNSKEY  ( 257 3 13
           Uf24EyNt51DMcLV+dHPInhSpmjPnqAQNUTouU+SGLu+lFRRlBetgw1bJUZNI6
           Dlger0VJTm0QuX/JVXcyGVGoQ== ) ; Key ID = 49352
   org.  86400  IN  DNSKEY  ( 257 3 13
           0SZfoe8Yx+eoaGgyAGEeJax/ZBV1AuG+/smcOgRm+F6doNlgc3lddcM1MbTvJ
           HTjK6Fvy8W6yZ+cAptn8sQheg== ) ; Key ID = 12651
   org.  86400  IN  RRSIG  ( DNSKEY 13 1 86400 20201202000000
           20181128000000 12651 org.
           Gq9wf+z3pasXXUwE210jYc0LhJnMAhcwXydnvkHtCVY6/0jUafHO4RksN84Zt
           us0pUgWngbT/OWXskdMYXZU4A== )
   org.  86400  IN  RRSIG  ( DNSKEY 13 1 86400 20201202000000
           20181128000000 49352 org.
           VGEkEMWBJ2IbOpm2Z56Qxu2NGPcVUDWCbYRyk+Qk1+HzGtyd2qPEKkpgMs/0p
           vZEMj1YXD+dIqb2nUK9PGBAXw== )
   org.  86400  IN  DS  ( 12651 13 2 3979a51f98bbf219fcaf4a4176e766dfa8f
           9db5c24a75743eb1e704b97a9fabc )
   org.  86400  IN  DS  ( 49352 13 2 03d11a1aa114abbb8f708c3c0ff0db765fe
           f4a2f18920db5f58710dd767c293b )
   org.  86400  IN  RRSIG  ( DS 13 1 86400 20201202000000
           20181128000000 31918 .
           adiFuP2UIulQw5Edsb/7WSPqr5nkRSTVXbZ2tkBeZRQcMjdCD3pyonWO5JPRV
           EemgaE357S4pX5D0tVZzeZJ6A== )
   .  86400  IN  DNSKEY  ( 256 3 13
           zKz+DCWkNA/vuheiVPcGqsH40U84KZAlrMRIyozj9WHzf8PsFp/oR8j8vmjjW
           P98cbte4d8NvlGLxzbUzo3+FA== ) ; Key ID = 31918
   .  86400  IN  DNSKEY  ( 256 3 13
           8wMZZ4lzHdyKZ4fv8kys/t3QMlgvEadbsbyqWrMhwddSXCZYGRrsAbPpireRW
           xbVcd1VtOrlFBcRDMTN0R0XEQ== ) ; Key ID = 2635
   .  86400  IN  DNSKEY  ( 257 3 13
           yvX+VNTUjxZiGvtr060hVbrPV9H6rVusQtF9lIxCFzbZOJxMQBFmbqlc8Xclv
           Q+gDOXnFOTsgs/frMmxyGOtRg== ) ; Key ID = 47005
   .  86400  IN  RRSIG  ( DNSKEY 13 0 86400 20201202000000
           20181128000000 47005 .
           0EPW1ca+N/ZhZPKla77STG734cTeIOjUwq7eW0HsnOfudWmnCEVeco2wLLq9m
           nBT1dtNjIczvLG9pQTnOKUsHQ== )

A.5.  "_443._tcp.www.example.net" DNAME

   example.net.  3600  IN  DNAME  example.com.
   example.net.  3600  IN  RRSIG  ( DNAME 13 2 3600 20201202000000
           20181128000000 48085 example.net.
           o3uV5k5Ewp5fdrOZt0n4QuH+/Hpku2Lo3CzGRt9/MS2zZt2Qb/AXz435UFQBx
           OI/pDnjJcLSd/gBLtqR52WLMA== )
   ; _443._tcp.www.example.net.  3600  IN  CNAME  (
   ;         _443._tcp.www.example.com. )
   _443._tcp.www.example.com.  3600  IN  TLSA  ( 3 1 1
           8bd1da95272f7fa4ffb24137fc0ed03aae67e5c4d8b3c50734e1050a7920b
           922 )
   _443._tcp.www.example.com.  3600  IN  RRSIG  ( TLSA 13 5 3600
           20201202000000 20181128000000 1870 example.com.
           rqY69NnTf4CN3GBGQjKEJCLAMsRkUrXe0JW8IqDb5rQHHzxNqqPeEoi+2vI6S
           z2BhaswpGLVVuoijuVdzxYjmw== )
   example.net.  3600  IN  DNSKEY  ( 257 3 13
           X9GHpJcS7bqKVEsLiVAbddHUHTZqqBbVa3mzIQmdp+5cTJk7qDazwH68Kts8d
           9MvN55HddWgsmeRhgzePz6hMg== ) ; Key ID = 48085
   example.net.  3600  IN  RRSIG  ( DNSKEY 13 2 3600
           20201202000000 20181128000000 48085 example.net.
           CkwqgEt1p97oMa3w5LctIjKIuG5XVSapKrfwuHhb5p04fWXRMNsXasG/kd2F/
           wlmMWiq38gOQaYCLNm+cjQzpQ== )
   example.net.  172800  IN  DS  ( 48085 13 2 7c1998ce683df60e2fa41460c4
           53f88f463dac8cd5d074277b4a7c04502921be )
   example.net.  172800  IN  RRSIG  ( DS 13 2 172800
           20201202000000 20181128000000 10713 net.
           w0JxDeiBJZNlpCdxKtRENlqfTpSxcs6Vftscsyfo/hyeTPYcIt4yItDkYsYK+
           KQ6FYAVE4nisA3vDQoZVL4wow== )
   net.  172800  IN  DNSKEY  ( 256 3 13
           061EoQs4sBcDsPiz17vt4nFSGLmXAGguqLStOesmKNCimi4/lw/vtyfqALuLF
           JiFjtCK3HMPi8HQ1jbGEwbGCA== ) ; Key ID = 10713
   net.  172800  IN  DNSKEY  ( 257 3 13
           LkNCPE+v3S4MVnsOqZFhn8n2NSwtLYOZLZjjgVsAKgu4XZncaDgq1R/7ZXRO5
           oVx2zthxuu2i+mGbRrycAaCvA== ) ; Key ID = 485
   net.  172800  IN  RRSIG  ( DNSKEY 13 1 172800 20201202000000
           20181128000000 485 net.
           031jXg06zSuDwI5zqYuYFJg1O5p+zy85csMXagvRxB9W2lL/wJRi6Gn9BcaCV
           RnDId5WR+yCADhsbKfSrrd9vQ== )
   net.  86400  IN  DS  ( 485 13 2 ab25a2941aa7f1eb8688bb783b25587515a0c
           d8c247769b23adb13ca234d1c05 )
   net.  86400  IN  RRSIG  ( DS 13 1 86400 20201202000000
           20181128000000 31918 .
           vOXoTjxggGTYKIwssQ3kpML0ag6D0Hcm+Syy7++4zT7gaFHfRH9a6uZekIWdb
           oss8y7q4onW4rxKdtw2S28hwQ== )
   .  86400  IN  DNSKEY  ( 256 3 13
           zKz+DCWkNA/vuheiVPcGqsH40U84KZAlrMRIyozj9WHzf8PsFp/oR8j8vmjjW
           P98cbte4d8NvlGLxzbUzo3+FA== ) ; Key ID = 31918
   .  86400  IN  DNSKEY  ( 256 3 13
           8wMZZ4lzHdyKZ4fv8kys/t3QMlgvEadbsbyqWrMhwddSXCZYGRrsAbPpireRW
           xbVcd1VtOrlFBcRDMTN0R0XEQ== ) ; Key ID = 2635
   .  86400  IN  DNSKEY  ( 257 3 13
           yvX+VNTUjxZiGvtr060hVbrPV9H6rVusQtF9lIxCFzbZOJxMQBFmbqlc8Xclv
           Q+gDOXnFOTsgs/frMmxyGOtRg== ) ; Key ID = 47005
   .  86400  IN  RRSIG  ( DNSKEY 13 0 86400 20201202000000
           20181128000000 47005 .
           0EPW1ca+N/ZhZPKla77STG734cTeIOjUwq7eW0HsnOfudWmnCEVeco2wLLq9m
           nBT1dtNjIczvLG9pQTnOKUsHQ== )
   example.com.  3600  IN  DNSKEY  ( 257 3 13
           JnA1XgyJTZz+psWvbrfUWLV6ULqIJyUS2CQdhUH9VK35bslWeJpRzrlxCUs7s
           /TsSfZMaGWVvlsuieh5nHcXzA== ) ; Key ID = 1870
   example.com.  3600  IN  RRSIG  ( DNSKEY 13 2 3600
           20201202000000 20181128000000 1870 example.com.
           nYisnu/26Sw1qmGuREa9o/fLgYuA4oNPt4+6PMBZoN0MS8Gjtli9NVRYeSIzt
           QHPGSpvRxTUC4tZi62z1UgGDw== )
   example.com.  172800  IN  DS  ( 1870 13 2 e9b533a049798e900b5c29c90cd
           25a986e8a44f319ac3cd302bafc08f5b81e16 )
   example.com.  172800  IN  RRSIG  ( DS 13 2 172800
           20201202000000 20181128000000 34327 com.
           sEAKvX4H6pJfN8nKcclB1NRcRSPOztx8omr4fCSHu6lp+uESP/Le4iF2sKukO
           J1hhWSB6jgubEVl17rGNOA/YQ== )
   com.  172800  IN  DNSKEY  ( 256 3 13
           7IIE5Dol8jSMUqHTvOOiZapdEbQ9wqRxFi/zQcSdufUKLhpByvLpzSAQTqCWj
           3URIZ8L3Fa2gBLMOZUzZ1GQCw== ) ; Key ID = 34327
   com.  172800  IN  DNSKEY  ( 257 3 13
           RbkcO+96XZmnp8jYIuM4lryAp3egQjSmBaSoiA7H76Tm0RLHPNPUxlVk+nQ0f
           Ic3I8xfZDNw8Wa0Pe3/g2QA/w== ) ; Key ID = 18931
   com.  172800  IN  DNSKEY  ( 257 3 13
           szc7biLo5J4OHlkan1vZrF4aD4YYf+NHA/GAqdNslY9xxK9Izg68XHkqck4Rt
           DiVk37lNAQmgSlHbrGu0yOTkA== ) ; Key ID = 28809
   com.  172800  IN  RRSIG  ( DNSKEY 13 1 172800 20201202000000
           20181128000000 18931 com.
           LJ4p5ORS2ViILwTotSlWixElqRXHY5tOdIuHlPWTdBGPMq3y40QNr1V+ZOyA5
           7LFdPKpcvb8BvhM+GqKWGBEsg== )
   com.  172800  IN  RRSIG  ( DNSKEY 13 1 172800 20201202000000
           20181128000000 28809 com.
           sO+4X2N21yS6x8+dBVBzbRo9+55MM8n7+RUvdBuxRFVh6JaBlqDOC5LLkl7Ev
           mDXqz6KEhhQjT+aQWDt6WFHlA== )
   com.  86400  IN  DS  ( 18931 13 2 20f7a9db42d0e2042fbbb9f9ea015941202
           f9eabb94487e658c188e7bcb52115 )
   com.  86400  IN  DS  ( 28809 13 2 ad66b3276f796223aa45eda773e92c6d98e
           70643bbde681db342a9e5cf2bb380 )
   com.  86400  IN  RRSIG  ( DS 13 1 86400 20201202000000
           20181128000000 31918 .
           nDiDlBjXEE/6AudhC++Hui1ckPcuAnGbjEASNoxA3ZHjlXRzL050UzePko5Pb
           vBKTf6pk8JRCqnfzlo2QY+WXA== )

A.6.  "_25._tcp.smtp.example.com" NSEC Denial of Existence

   smtp.example.com.  3600  IN  NSEC  ( www.example.com. A AAAA
           RRSIG NSEC )
   smtp.example.com.  3600  IN  RRSIG  ( NSEC 13 3 3600
           20201202000000 20181128000000 1870 example.com.
           rH/K4wghCOm4jpEHwQKiyZzvFIa7qpFySuKIGGetW4SE4O2Mh5jPxcEzf78Hf
           crlsQZmnAUlfmBNCygxAd7JNw== )
   example.com.  3600  IN  DNSKEY  ( 257 3 13
           JnA1XgyJTZz+psWvbrfUWLV6ULqIJyUS2CQdhUH9VK35bslWeJpRzrlxCUs7s
           /TsSfZMaGWVvlsuieh5nHcXzA== ) ; Key ID = 1870
   example.com.  3600  IN  RRSIG  ( DNSKEY 13 2 3600
           20201202000000 20181128000000 1870 example.com.
           nYisnu/26Sw1qmGuREa9o/fLgYuA4oNPt4+6PMBZoN0MS8Gjtli9NVRYeSIzt
           QHPGSpvRxTUC4tZi62z1UgGDw== )
   example.com.  172800  IN  DS  ( 1870 13 2 e9b533a049798e900b5c29c90cd
           25a986e8a44f319ac3cd302bafc08f5b81e16 )
   example.com.  172800  IN  RRSIG  ( DS 13 2 172800
           20201202000000 20181128000000 34327 com.
           sEAKvX4H6pJfN8nKcclB1NRcRSPOztx8omr4fCSHu6lp+uESP/Le4iF2sKukO
           J1hhWSB6jgubEVl17rGNOA/YQ== )
   com.  172800  IN  DNSKEY  ( 256 3 13
           7IIE5Dol8jSMUqHTvOOiZapdEbQ9wqRxFi/zQcSdufUKLhpByvLpzSAQTqCWj
           3URIZ8L3Fa2gBLMOZUzZ1GQCw== ) ; Key ID = 34327
   com.  172800  IN  DNSKEY  ( 257 3 13
           RbkcO+96XZmnp8jYIuM4lryAp3egQjSmBaSoiA7H76Tm0RLHPNPUxlVk+nQ0f
           Ic3I8xfZDNw8Wa0Pe3/g2QA/w== ) ; Key ID = 18931
   com.  172800  IN  DNSKEY  ( 257 3 13
           szc7biLo5J4OHlkan1vZrF4aD4YYf+NHA/GAqdNslY9xxK9Izg68XHkqck4Rt
           DiVk37lNAQmgSlHbrGu0yOTkA== ) ; Key ID = 28809
   com.  172800  IN  RRSIG  ( DNSKEY 13 1 172800 20201202000000
           20181128000000 18931 com.
           LJ4p5ORS2ViILwTotSlWixElqRXHY5tOdIuHlPWTdBGPMq3y40QNr1V+ZOyA5
           7LFdPKpcvb8BvhM+GqKWGBEsg== )
   com.  172800  IN  RRSIG  ( DNSKEY 13 1 172800 20201202000000
           20181128000000 28809 com.
           sO+4X2N21yS6x8+dBVBzbRo9+55MM8n7+RUvdBuxRFVh6JaBlqDOC5LLkl7Ev
           mDXqz6KEhhQjT+aQWDt6WFHlA== )
   com.  86400  IN  DS  ( 18931 13 2 20f7a9db42d0e2042fbbb9f9ea015941202
           f9eabb94487e658c188e7bcb52115 )
   com.  86400  IN  DS  ( 28809 13 2 ad66b3276f796223aa45eda773e92c6d98e
           70643bbde681db342a9e5cf2bb380 )
   com.  86400  IN  RRSIG  ( DS 13 1 86400 20201202000000
           20181128000000 31918 .
           nDiDlBjXEE/6AudhC++Hui1ckPcuAnGbjEASNoxA3ZHjlXRzL050UzePko5Pb
           vBKTf6pk8JRCqnfzlo2QY+WXA== )
   .  86400  IN  DNSKEY  ( 256 3 13
           zKz+DCWkNA/vuheiVPcGqsH40U84KZAlrMRIyozj9WHzf8PsFp/oR8j8vmjjW
           P98cbte4d8NvlGLxzbUzo3+FA== ) ; Key ID = 31918
   .  86400  IN  DNSKEY  ( 256 3 13
           8wMZZ4lzHdyKZ4fv8kys/t3QMlgvEadbsbyqWrMhwddSXCZYGRrsAbPpireRW
           xbVcd1VtOrlFBcRDMTN0R0XEQ== ) ; Key ID = 2635
   .  86400  IN  DNSKEY  ( 257 3 13
           yvX+VNTUjxZiGvtr060hVbrPV9H6rVusQtF9lIxCFzbZOJxMQBFmbqlc8Xclv
           Q+gDOXnFOTsgs/frMmxyGOtRg== ) ; Key ID = 47005
   .  86400  IN  RRSIG  ( DNSKEY 13 0 86400 20201202000000
           20181128000000 47005 .
           0EPW1ca+N/ZhZPKla77STG734cTeIOjUwq7eW0HsnOfudWmnCEVeco2wLLq9m
           nBT1dtNjIczvLG9pQTnOKUsHQ== )

A.7.  "_25._tcp.smtp.example.org" NSEC3 Denial of Existence

   vkv62jbv85822q8rtmfnbhfnmnat9ve3.example.org.  3600  IN  NSEC3  (
           1 0 1 - 93u63bg57ppj6649al2n31l92iedkjd6 A AAAA RRSIG )
   vkv62jbv85822q8rtmfnbhfnmnat9ve3.example.org.  3600  IN  RRSIG  (
           NSEC3 13 3 3600 20201202000000 20181128000000 56566
           example.org.
           wn3cePVdc5VPPniYzGp+1CBPOY2m83/A3cjnAb7FTZuwL45B25fwVUyjKQksh
           gQeV5KgP1cdvPt1BEowKqK4Sw== )
   dlm7rss9pejqnh0ev6h7k1ikqqcl5mae.example.org.  3600  IN  NSEC3  (
           1 0 1 - t6lf7uuoi0qofq0nvdjroavo46pp20im RRSIG TLSA )
   dlm7rss9pejqnh0ev6h7k1ikqqcl5mae.example.org.  3600  IN  RRSIG  (
           NSEC3 13 3 3600 20201202000000 20181128000000 56566
           example.org.
           guUyy9LIZlYb0FZttAdYJGrFNKpKu91Tm+dPOz98rnpwIlwwvLifXIvIl90nE
           X38cWzEQOpreJu3t4WAfPsxdg== )
   a73bi8coh6dvf1arqdeuogf95r0828mk.example.org.  3600  IN  NSEC3  (
           1 0 1 - c1p0lp7l1l8gdn0jl13pp1o41h35untj CNAME RRSIG )
   a73bi8coh6dvf1arqdeuogf95r0828mk.example.org.  3600  IN  RRSIG  (
           NSEC3 13 3 3600 20201202000000 20181128000000 56566
           example.org.
           ePBUuWdj8Bc+/41gHBm2Bx/IK/j/Q4W7A5uTgSj/0Sd57mP/NTWRZq3p8yBNe
           FPC2mBJ2oWQFi6/V9dmyiBh2A== )
   example.org.  3600  IN  DNSKEY  ( 256 3 13
           NrbL6utGqIW1wrhhjeexdA6bMdD1lC1hj0Fnpevaa1AMyY2uy83TmoGnR996N
           UR5TlG4Zh+YPbbmUIixe4nS3w== ) ; Key ID = 56566
   example.org.  3600  IN  DNSKEY  ( 257 3 13
           uspaqp17jsMTX6AWVgmbog/3Sttz+9ANFUWLn6qKUHr0BOqRuChQWj8jyYUUr
           Wy9txxesNQ9MkO4LUrFght1LQ== ) ; Key ID = 44384
   example.org.  3600  IN  RRSIG  ( DNSKEY 13 2 3600
           20201202000000 20181128000000 44384 example.org.
           ttse9pYp9PSu0pJ+TOpIVFLWJ6NKOMWZX4Q/SlU6ZfaiKQc0Bg7Tut9+wPunk
           6OPPvyHjVXMAsvk0tqV0B+/ag== )
   example.org.  86400  IN  DS  ( 44384 13 2 ec307e2efc8f0117ed96ab48a51
           3c8003e1d9121f1ff11a08b4cdd348d090aa6 )
   example.org.  86400  IN  RRSIG  ( DS 13 2 86400 20201202000000
           20181128000000 9523 org.
           m86Xz0CEa2sWG40a0bS2kqLKPmIlyiVyDeoWXAq3djeGiPaikLuKORNzWXu62
           clpAfvZHx59Ackst4X+zXYpUA== )
   org.  86400  IN  DNSKEY  ( 256 3 13
           fuLp60znhSSEr9HowILpTpyLKQdM6ixcgkTE0gqVdsLx+DSNHSc69o6fLWC0e
           HfWx7kzlBBoJB0vLrvsJtXJ6g== ) ; Key ID = 47417
   org.  86400  IN  DNSKEY  ( 256 3 13
           zTHbb7JM627Bjr8CGOySUarsic91xZU3vvLJ5RjVix9YH6+iwpBXb6qfHyQHy
           mlMiAAoaoXh7BUkEBVgDVN8sQ== ) ; Key ID = 9523
   org.  86400  IN  DNSKEY  ( 257 3 13
           Uf24EyNt51DMcLV+dHPInhSpmjPnqAQNUTouU+SGLu+lFRRlBetgw1bJUZNI6
           Dlger0VJTm0QuX/JVXcyGVGoQ== ) ; Key ID = 49352
   org.  86400  IN  DNSKEY  ( 257 3 13
           0SZfoe8Yx+eoaGgyAGEeJax/ZBV1AuG+/smcOgRm+F6doNlgc3lddcM1MbTvJ
           HTjK6Fvy8W6yZ+cAptn8sQheg== ) ; Key ID = 12651
   org.  86400  IN  RRSIG  ( DNSKEY 13 1 86400 20201202000000
           20181128000000 12651 org.
           Gq9wf+z3pasXXUwE210jYc0LhJnMAhcwXydnvkHtCVY6/0jUafHO4RksN84Zt
           us0pUgWngbT/OWXskdMYXZU4A== )
   org.  86400  IN  RRSIG  ( DNSKEY 13 1 86400 20201202000000
           20181128000000 49352 org.
           VGEkEMWBJ2IbOpm2Z56Qxu2NGPcVUDWCbYRyk+Qk1+HzGtyd2qPEKkpgMs/0p
           vZEMj1YXD+dIqb2nUK9PGBAXw== )
   org.  86400  IN  DS  ( 12651 13 2 3979a51f98bbf219fcaf4a4176e766dfa8f
           9db5c24a75743eb1e704b97a9fabc )
   org.  86400  IN  DS  ( 49352 13 2 03d11a1aa114abbb8f708c3c0ff0db765fe
           f4a2f18920db5f58710dd767c293b )
   org.  86400  IN  RRSIG  ( DS 13 1 86400 20201202000000
           20181128000000 31918 .
           adiFuP2UIulQw5Edsb/7WSPqr5nkRSTVXbZ2tkBeZRQcMjdCD3pyonWO5JPRV
           EemgaE357S4pX5D0tVZzeZJ6A== )
   .  86400  IN  DNSKEY  ( 256 3 13
           zKz+DCWkNA/vuheiVPcGqsH40U84KZAlrMRIyozj9WHzf8PsFp/oR8j8vmjjW
           P98cbte4d8NvlGLxzbUzo3+FA== ) ; Key ID = 31918
   .  86400  IN  DNSKEY  ( 256 3 13
           8wMZZ4lzHdyKZ4fv8kys/t3QMlgvEadbsbyqWrMhwddSXCZYGRrsAbPpireRW
           xbVcd1VtOrlFBcRDMTN0R0XEQ== ) ; Key ID = 2635
   .  86400  IN  DNSKEY  ( 257 3 13
           yvX+VNTUjxZiGvtr060hVbrPV9H6rVusQtF9lIxCFzbZOJxMQBFmbqlc8Xclv
           Q+gDOXnFOTsgs/frMmxyGOtRg== ) ; Key ID = 47005
   .  86400  IN  RRSIG  ( DNSKEY 13 0 86400 20201202000000
           20181128000000 47005 .
           0EPW1ca+N/ZhZPKla77STG734cTeIOjUwq7eW0HsnOfudWmnCEVeco2wLLq9m
           nBT1dtNjIczvLG9pQTnOKUsHQ== )

A.8.  "_443._tcp.www.insecure.example" NSEC3 Opt-Out Insecure Delegation

   c1kgc91hrn9nqi2qjh1ms78ki8p7s75o.example.  43200  IN  NSEC3  (
           1 1 1 - shn05itmoa45mmnv74lc4p0nnfmimtjt NS SOA RRSIG DNSKEY
           NSEC3PARAM )
   c1kgc91hrn9nqi2qjh1ms78ki8p7s75o.example.  43200  IN  RRSIG  (
           NSEC3 13 2 43200 20201202000000 20181128000000 15903
           example.
           pW16gQOLhLpKYgXpGt4XB4o92W/QoPYyG5CjQ+t+g7LBVcCiPQv8ars1j9UOg
           RpXUsJhZBDax2dfDhK7zOk7ow== )
   shn05itmoa45mmnv74lc4p0nnfmimtjt.example.  43200  IN  NSEC3  (
           1 1 1 - a3ib1dvf1bdtfmd91usrdem5fiiepi6p NS DS RRSIG )
   shn05itmoa45mmnv74lc4p0nnfmimtjt.example.  43200  IN  RRSIG  (
           NSEC3 13 2 43200 20201202000000 20181128000000 15903
           example.
           5Aq//A8bsWNwcXbT91pMX2Oqf8VpJQRjqH4D2yZElW00wKmt85mhgu2qYPrvH
           QwGEB4STMz2Nefq01/GY6NHKg== )
   example.  432000  IN  DNSKEY  ( 257 3 13
           yrkqXSbVwXOoUxCjr/E9yg8XUzbZNlwPllVsoUPd73TLOnBQQ+03Qw4/k+Nme
           /66WIw+ZTlHYcTNalxiGYm0uQ== ) ; Key ID = 15903
   example.  432000  IN  RRSIG  ( DNSKEY 13 1 432000
           20201202000000 20181128000000 15903 example.
           wwEo3ri6JBuCqx5b33w8axFWOhIen1l+/mm0Isyc9FciuLhBiP+IqSgt+Igc8
           9nR8zRpJpo1D6XR/qJxZgnfaA== )
   example.  86400  IN  DS  ( 15903 13 2 7e0ebaf1cc0d309d4a73ca7d711719d
           d940f4da87b3d72865167650fc73ea577 )
   example.  86400  IN  RRSIG  ( DS 13 1 86400 20201202000000
           20181128000000 31918 .
           B5vx4zZaS+bOYfz0PzpaPfk9VxxBvYbGjIvGhpUZV3diXzfCguXxN4JIT1Sz8
           eJX6BYT5QPIrbG/N35U1sIskw== )
   .  86400  IN  DNSKEY  ( 256 3 13
           zKz+DCWkNA/vuheiVPcGqsH40U84KZAlrMRIyozj9WHzf8PsFp/oR8j8vmjjW
           P98cbte4d8NvlGLxzbUzo3+FA== ) ; Key ID = 31918
   .  86400  IN  DNSKEY  ( 256 3 13
           8wMZZ4lzHdyKZ4fv8kys/t3QMlgvEadbsbyqWrMhwddSXCZYGRrsAbPpireRW
           xbVcd1VtOrlFBcRDMTN0R0XEQ== ) ; Key ID = 2635
   .  86400  IN  DNSKEY  ( 257 3 13
           yvX+VNTUjxZiGvtr060hVbrPV9H6rVusQtF9lIxCFzbZOJxMQBFmbqlc8Xclv
           Q+gDOXnFOTsgs/frMmxyGOtRg== ) ; Key ID = 47005
   .  86400  IN  RRSIG  ( DNSKEY 13 0 86400 20201202000000
           20181128000000 47005 .
           0EPW1ca+N/ZhZPKla77STG734cTeIOjUwq7eW0HsnOfudWmnCEVeco2wLLq9m
           nBT1dtNjIczvLG9pQTnOKUsHQ== )

Acknowledgments

   Many thanks to Adam Langley for laying the groundwork for this
   extension in [SERIALIZECHAIN].  The original idea is his, but our
   acknowledgment in no way implies his endorsement.  This document also
   benefited from discussions with and review from the following people:
   Daniel Kahn Gillmor, Jeff Hodges, Allison Mankin, Patrick McManus,
   Rick van Rein, Ilari Liusvaara, Eric Rescorla, Gowri Visweswaran,
   Duane Wessels, Nico Williams, and Richard Barnes.

Authors' Addresses

   Viktor Dukhovni
   Two Sigma

   Email: ietf-dane@dukhovni.org


   Shumon Huque
   Salesforce
   3rd Floor
   415 Mission Street
   San Francisco, CA 94105
   United States of America

   Email: shuque@gmail.com


   Willem Toorop
   NLnet Labs
   Science Park 400
   1098 XH Amsterdam
   Netherlands

   Email: willem@nlnetlabs.nl


   Paul Wouters
   Aiven
   Toronto
   Canada

   Email: paul.wouters@aiven.io


   Melinda Shore
   Fastly

   Email: mshore@fastly.com