path: root/doc/rfc/rfc9537.txt

Internet Engineering Task Force (IETF)                          J. Gould
Request for Comments: 9537                                      D. Smith
Category: Standards Track                                 VeriSign, Inc.
ISSN: 2070-1721                                                J. Kolker
                                                               R. Carney
                                                            GoDaddy Inc.
                                                              March 2024


Redacted Fields in the Registration Data Access Protocol (RDAP) Response

Abstract

   This document describes a Registration Data Access Protocol (RDAP)
   extension for specifying methods of redaction of RDAP responses and
   explicitly identifying redacted RDAP response fields, using JSONPath
   as the default expression language.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in 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/rfc9537.

Copyright Notice

   Copyright (c) 2024 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.  Code Components extracted from this document must
   include Revised BSD License text as described in Section 4.e of the
   Trust Legal Provisions and are provided without warranty as described
   in the Revised BSD License.

Table of Contents

   1.  Introduction
   2.  Conventions Used in This Document
   3.  Redaction Methods
     3.1.  Redaction by Removal Method
     3.2.  Redaction by Empty Value Method
     3.3.  Redaction by Partial Value Method
     3.4.  Redaction by Replacement Value Method
   4.  Redacted RDAP Response
     4.1.  RDAP Conformance
     4.2.  "redacted" Member
   5.  JSONPath Considerations
     5.1.  JSONPath Client Considerations
     5.2.  JSONPath Server Considerations
   6.  IANA Considerations
     6.1.  RDAP Extensions Registry
     6.2.  RDAP JSON Values Registry
   7.  Security Considerations
   8.  References
     8.1.  Normative References
     8.2.  Informative References
   Acknowledgements
   Authors' Addresses

1.  Introduction

   This document describes an RDAP extension for specifying methods of
   redaction of RDAP responses and explicitly identifying redacted RDAP
   response fields, using JSONPath as the default expression language.
   A redacted RDAP field is one that has data removed or replaced in the
   RDAP response due to server policy, such as the lack of client
   privilege to receive the field.  This extension can be used to
   identify redacted RDAP fields in any RDAP object class, as defined in
   [RFC9083], or RDAP fields defined in RDAP extensions.  Because an
   RDAP response may exclude a field due to either the lack of data or
   the lack of RDAP client privileges, this extension is used to
   explicitly specify which RDAP fields are not included in the RDAP
   response due to redaction.  It thereby provides a capability for
   disambiguation between redaction and other possible reasons for data
   or field absence.

   In [RFC9082], RDAP supports both lookup and search queries, where a
   lookup query responds with a single object and a search query
   responds with a list of objects.  This document applies to redaction
   of a single object of a lookup response and in each of the objects of
   a search response.

   JSONPath, as defined in [RFC9535], is used as the default expression
   language to reference RDAP fields that have been redacted.  The
   redacted JSON fields will be removed, have empty values, have partial
   values, or be replaced in the RDAP response.  JSON is defined by
   [RFC8259].

2.  Conventions Used in This Document

   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.

   The JSON examples include extra line breaks and empty space.  For
   instance, the JSONPath expressions are broken out into multiple lines
   when required for illustration.

   The JSONPath expressions in the examples are for illustration
   purposes with single-role entities, and the exact expressions to be
   used by the server are out of scope.

3.  Redaction Methods

   Redaction in RDAP can be handled in multiple ways.  The resulting
   redacted RDAP response MUST comply with the format defined in the
   RDAP RFCs, such as [RFC9083] and updates.  The use of placeholder
   text for the values of the RDAP fields, such as "XXXX", MUST NOT be
   used for redaction, since the placeholder text value may not match
   the format requirements of each of the RDAP fields, which could
   provide an inconsistent and unreliable redaction signal.  This
   section covers the redaction methods that can be used with the
   redaction signaling defined in Section 4.2.

   RDAP responses, as defined in [RFC9083], include a mix of JSON
   objects and JSON arrays, where JSON arrays are heavily used for
   entity objects with jCard [RFC7095].  jCard is a JSON representation
   of vCard [RFC6350] that inherits its dependency on arrays.  An
   example is the vCard "ADR" property [RFC6350], or the jCard "adr"
   property [RFC7095], which defines a sequence of address components.
   According to [RFC6350], when an "ADR" property component value is
   missing, the associated component separator MUST still be specified.
   jCard extends the use of arrays with each individual vCard property
   being represented by an array of three fixed elements, followed by
   one or more additional elements.  The mix of JSON objects and JSON
   arrays impacts the methods used for redaction in RDAP.

   The redaction of RDAP fields fall into the four categories defined in
   the following subsections.

3.1.  Redaction by Removal Method

   The Redaction by Removal Method is when the RDAP field is removed
   from the RDAP response, which is the default method.  The Redaction
   by Removal Method can be done for all RDAP response fields except for
   response fields using the position in an array to signal the redacted
   field (e.g., the JSON arrays used with jCard).  RDAP extensions, such
   as the one described in "Using JSContact in Registration Data Access
   Protocol (RDAP) JSON Responses" [RDAP-JSCONTACT], do not have a
   dependency on the use of positional JSON arrays and are therefore
   suited for the Redaction by Removal Method.

   When an RDAP object is redacted by removal, all of the RDAP object's
   child fields are also removed.  Only the redacted RDAP object needs
   to be referenced in the list of redacted fields, as defined in
   Section 4.2.

   An example of redacting an RDAP object is removing the administrative
   contact from the RDAP response and including the following "redacted"
   member:

   "redacted": [
     {
       "name": {
         "description": "Administrative Contact"
       },
       "prePath": "$.entities[?(@.roles[0]=='administrative')]",
       "method": "removal"
     }
   ]

                 Figure 1: Redacted Administrative Contact

   The Redaction by Removal Method MUST NOT be used to remove an element
   of an array where the position of the element in the array determines
   semantic meaning.  For example, removal of an individual data field
   in jCard will result in a non-conformant jCard array definition.

3.2.  Redaction by Empty Value Method

   The Redaction by Empty Value Method is when a redacted field is not
   removed but its value is set to an empty value, such as "" for a
   jCard text ("text") property or null for a non-text property.  The
   empty jCard values ("" or null) are referenced in the "redacted"
   member in place of the jCard property name in an array, such as
   referencing the "fn" jCard property value at position 3 instead of
   referencing the "fn" jCard property name at position 0.  The
   Redaction by Empty Value Method MUST be used only when redacting JSON
   response fields that use the position in an array to signal the
   redacted field (e.g., jCard arrays).  Optional jCard properties MUST
   use the Redaction by Removal Method (Section 3.1) to redact the
   entire property.  The required jCard "fn" property, defined in
   Section 6.2.1 of vCard [RFC6350], MUST use the Redaction by Empty
   Value Method to redact the property value.  Removing the "fn"
   property would violate vCard [RFC6350], and removing the property
   value would violate the fixed array positions defined in jCard.

   [
     "fn",
     {},
     "text",
     ""
   ]

       Figure 2: Redacted "fn" jCard Property Using the Redaction by
                             Empty Value Method

   An example of the "redacted" member for the redacted "fn" jCard
   property value, which is array position 3:

   "redacted": [
     {
       "name": {
         "description": "Registrant Name"
       },
       "postPath": "$.entities[?(@.roles[0]=='registrant')].
         vcardArray[1][?(@[0]=='fn')][3]",
       "pathLang": "jsonpath",
       "method": "emptyValue",
       "reason": {
         "description": "Server policy"
       }
     }
   ]

         Figure 3: Redacted Registrant Name Using an Array Position

3.3.  Redaction by Partial Value Method

   The Redaction by Partial Value Method is when a redacted field is not
   removed but its value has a portion of the data removed, such as for
   the "label" or "fn" jCard properties.  The partial values are
   referenced in the "redacted" member in place of the property name in
   an array, such as referencing the "fn" jCard property value at
   position 3 instead of referencing the "fn" jCard property name at
   position 0.  The Redaction by Partial Value Method SHOULD be used
   only when redacting JSON response fields that use a formatted value,
   where a portion of the value is removed.

   An example of the "label" jCard property in Section 3.3.1.3 of
   [RFC7095] that redacts "123 Maple Ave\nSuite 901\n":

   ["adr",
     {
       "type":"home",
       "label":"Vancouver\nBC\n1239\n"
     },
     "text",
     [
       "", "", "", "", "", "", ""
     ]
   ]

                 Figure 4: Redacted "label" jCard Property

   An example of the "redacted" member for the redacted "label" jCard
   property value, based on Section 3.3.1.3 of [RFC7095]:

   "redacted": [
     {
       "name": {
         "description": "Home Address Label"
       },
       "postPath": "$.vcardArray[1][?(@[0]=='adr')][1].label",
       "pathLang": "jsonpath",
       "method": "partialValue",
       "reason": {
         "description": "Server policy"
       }
     }
   ]

    Figure 5: Redacted Label Using the Redaction by Partial Value Method

3.4.  Redaction by Replacement Value Method

   The Redaction by Replacement Value Method is when a redacted field is
   not removed but its value is replaced with a different value, such as
   protecting the "email" jCard property value with an anonymized email
   "text" value or the use of an alternative "uri" value to a web form.
   Replacing a property value is a form of redaction, since it protects
   the true property value for privacy reasons.

   [
     "email",
     {},
     "text",
     "anonymized123@example.com"
   ]

      Figure 6: Redacted "email" jCard Property Using the Redaction by
             Replacement Value Method with an Anonymized Email

   "redacted": [
     {
       "name": {
         "description": "Registrant Email"
       },
       "postPath": "$.entities[?(@.roles[0]=='registrant')].
                  vcardArray[1][?(@[0]=='email')][3]",
       "pathLang": "jsonpath",
       "method": "replacementValue",
     }
   ]

         Figure 7: Redacted Email Using a Replacement Value with an
                          Anonymized "text" Value

   [
     "contact-uri",
     {},
     "uri",
     "https://email.example.com/123"
   ]

      Figure 8: Redacted "email" jCard Property Using the Redaction by
     Replacement Value Method with a "contact-uri" jCard Property to a
                                  Web Form

   "redacted": [
     {
       "name": {
         "description": "Registrant Email"
       },
       "prePath": "$.entities[?(@.roles[0]=='registrant')].
                  vcardArray[1][?(@[0]=='email')]",
       "replacementPath": "$.entities[?(@.roles[0]=='registrant')].
                  vcardArray[1][?(@[0]=='contact-uri')]",
       "pathLang": "jsonpath",
       "method": "replacementValue",
     }
   ]

         Figure 9: Redacted Email Using a Replacement Value with a
                 "contact-uri" jCard Property to a Web Form

4.  Redacted RDAP Response

4.1.  RDAP Conformance

   RDAP responses that contain values described in this document MUST
   indicate conformance with this specification by including an
   "rdapConformance" [RFC9083] value of "redacted".  The "redacted"
   extension identifier is described in Section 6.1.

   "rdapConformance": [
     "rdap_level_0",
     "redacted"
   ]

            Figure 10: "rdapConformance" with Redacted Extension

4.2.  "redacted" Member

   The "redacted" member MUST be added to the RDAP response when there
   is one or more redacted fields.  The "redacted" member is included as
   a member of the object instance in a lookup response, such as the
   object classes defined in [RFC9083], and as a member of the object
   instances in a search response.

   The server, including a redacted signal, provides an unauthorized
   client additional information related to the existence of data and
   MAY exclude the redacted members for RDAP fields that are considered
   a privacy issue in providing a data existence signal.  The server MAY
   choose to publish a redaction policy describing how this extension is
   implemented for their constituency.  The contents of such a policy
   are outside the scope of this specification.

   The "redacted" member contains an array of objects with the following
   child members:

   "name":  REQUIRED logical name for the redacted field.  The logical
       name used for the redacted field is up to server policy.  The
       logical name is defined using an object with a "type" field
       denoting a registered redacted name (see Section 6.2) or a
       "description" field denoting an unregistered redacted name.  The
       registered redacted names and the chosen unregistered names can
       meet the needs of different RDAP services or industries.

   "prePath":  OPTIONAL JSON path expression referencing a redacted JSON
       field in the pre-redacted response, using the expression language
       defined by the "pathLang" member.  The "prePath" member MAY be
       set when the redacted field does not exist in the redacted
       response for the Redaction by Removal Method (Section 3.1) and
       the Redaction by Replacement Value Method (Section 3.4).  The
       "prePath" member MUST NOT be set when the "postPath" member is
       set.

   "postPath":  OPTIONAL JSON path expression referencing a redacted
       JSON field in the redacted (post-redacted) response, using the
       expression language defined by the "pathLang" member.  The
       "postPath" member MUST be set when the redacted field does exist
       in the redacted response for the Redaction by Empty Value Method
       (Section 3.2), the Redaction by Partial Value Method
       (Section 3.3), and the Redaction by Replacement Value Method
       (Section 3.4).  The "postPath" member MUST NOT be set when the
       "prePath" member is set.

   "replacementPath":  OPTIONAL JSON path expression of the replacement
       field of the redacted field with the Redaction by Replacement
       Value Method (Section 3.4), using the expression language defined
       by the "pathLang" member.

   "pathLang":  OPTIONAL JSON path expression language used, with the
       default value of "jsonpath" for JSONPath [RFC9535].  Other JSON
       path expression languages registered with the "redacted
       expression language" Type in the "RDAP JSON Values" registry MAY
       be used based on server policy.

   "method":  OPTIONAL redaction method used, with one of the following
       values:

       *  "removal" indicating the Redaction by Removal Method
          (Section 3.1),

       *  "emptyValue" indicating the Redaction by Empty Value Method
          (Section 3.2),

       *  "partialValue" indicating the Redaction by Partial Value
          Method (Section 3.3), or

       *  "replacementValue" indicating the Redaction by Replacement
          Value Method (Section 3.4).

       The default value is "removal" when not provided.

   "reason":  OPTIONAL human-readable reason(s) for the redacted field
       in the language defined by the "lang" [RFC9083] member.  The
       default language is "en" if the "lang" [RFC9083] member is not
       specified.  The reason is defined using an object with an
       OPTIONAL "type" field denoting a registered redacted reason (see
       Section 6.2) and an OPTIONAL "description" field denoting an
       unregistered redacted reason.  The "description" field MUST NOT
       be a client processing dependency.

   Example of the unredacted version of an RDAP lookup response:

       {
         "rdapConformance": [
           "rdap_level_0"
         ],
         "objectClassName": "domain",
         "handle": "ABC123",
         "ldhName": "example.com",
         "secureDNS": {
           "delegationSigned": false
         },
         "notices": [
           {
             "title": "Terms of Use",
             "description": [
               "Service subject to Terms of Use."
             ],
             "links": [
               {
                 "rel": "self",
                 "href": "https://www.example.com/terms-of-use",
                 "type": "text/html",
                 "value": "https://www.example.com/terms-of-use"
               }
             ]
           }
         ],
         "nameservers": [
           {
             "objectClassName": "nameserver",
             "ldhName": "ns1.example.com"
           },
           {
             "objectClassName": "nameserver",
             "ldhName": "ns2.example.com"
           }
         ],
         "entities": [
           {
             "objectClassName": "entity",
             "handle": "123",
             "roles": [
               "registrar"
             ],
             "publicIds": [
               {
                 "type": "IANA Registrar ID",
                 "identifier": "1"
               }
             ],
             "vcardArray": [
               "vcard",
               [
                 [
                   "version",
                   {},
                   "text",
                   "4.0"
                 ],
                 [
                   "fn",
                   {},
                   "text",
                   "Example Registrar Inc."
                 ],
                 [
                   "adr",
                   {},
                   "text",
                   [
                     "",
                     "Suite 100",
                     "123 Example Dr.",
                     "Dulles",
                     "VA",
                     "20166-6503",
                     "US"
                   ]
                 ],
                 [
                   "email",
                   {},
                   "text",
                   "contact@organization.example"
                 ],
                 [
                   "tel",
                   {
                     "type": "voice"
                   },
                   "uri",
                   "tel:+1.7035555555;ext=1234"
                 ],
                 [
                   "tel",
                   {
                     "type": "fax"
                   },
                   "uri",
                   "tel:+1.7035555556"
                 ]
               ]
             ],
             "entities": [
               {
                 "objectClassName": "entity",
                 "roles": [
                   "abuse"
                 ],
                 "vcardArray": [
                   "vcard",
                   [
                     [
                       "version",
                       {},
                       "text",
                       "4.0"
                     ],
                     [
                       "fn",
                       {},
                       "text",
                       "Abuse Contact"
                     ],
                     [
                       "email",
                       {},
                       "text",
                       "abuse@organization.example"
                     ],
                     [
                       "tel",
                       {
                         "type": "voice"
                       },
                       "uri",
                       "tel:+1.7035555555;ext=1234"
                     ]
                   ]
                 ]
               }
             ]
           },
           {
             "objectClassName": "entity",
             "handle": "XXXX",
             "roles": [
               "registrant"
             ],
             "vcardArray": [
               "vcard",
               [
                 [
                   "version",
                   {},
                   "text",
                   "4.0"
                 ],
                 [
                   "fn",
                   {},
                   "text",
                   "Registrant User"
                 ],
                 [
                   "org",
                   {},
                   "text",
                   "Example Inc."
                 ],
                 [
                   "adr",
                   {},
                   "text",
                   [
                     "",
                     "Suite 1235",
                     "4321 Rue Somewhere",
                     "Quebec",
                     "QC",
                     "G1V 2M2",
                     "Canada"
                   ]
                 ],
                 [
                   "email",
                   {},
                   "text",
                   "registrant.user@example.com"
                 ],
                 [
                   "tel",
                   {
                     "type": "voice"
                   },
                   "uri",
                   "tel:+1-555-555-1235;ext=123"
                 ],
                 [
                   "tel",
                   {
                     "type": "fax"
                   },
                   "uri",
                   "tel:+1-555-555-5321"
                 ]
               ]
             ]
           },
           {
             "objectClassName": "entity",
             "handle": "YYYY",
             "roles": [
               "technical"
             ],
             "vcardArray": [
               "vcard",
               [
                 [
                   "version",
                   {},
                   "text",
                   "4.0"
                 ],
                 [
                   "fn",
                   {},
                   "text",
                   "Technical User"
                 ],
                 [
                   "org",
                   {},
                   "text",
                   "Example Inc."
                 ],
                 [
                   "adr",
                   {},
                   "text",
                   [
                     "",
                     "Suite 1234",
                     "4321 Rue Somewhere",
                     "Quebec",
                     "QC",
                     "G1V 2M2",
                     "Canada"
                   ]
                 ],
                 [
                   "email",
                   {},
                   "text",
                   "technical.user@example.com"
                 ],
                 [
                   "tel",
                   {
                     "type": "voice"
                   },
                   "uri",
                   "tel:+1-555-555-1234;ext=321"
                 ],
                 [
                   "tel",
                   {
                     "type": "fax"
                   },
                   "uri",
                   "tel:+1-555-555-4321"
                 ]
               ]
             ]
           },
           {
             "objectClassName": "entity",
             "handle": "ZZZZ",
             "roles": [
               "administrative"
             ],
             "vcardArray": [
               "vcard",
               [
                 [
                   "version",
                   {},
                   "text",
                   "4.0"
                 ],
                 [
                   "fn",
                   {},
                   "text",
                   "Administrative User"
                 ],
                 [
                   "org",
                   {},
                   "text",
                   "Example Inc."
                 ],
                 [
                   "adr",
                   {},
                   "text",
                   [
                     "",
                     "Suite 1236",
                     "4321 Rue Somewhere",
                     "Quebec",
                     "QC",
                     "G1V 2M2",
                     "Canada"
                   ]
                 ],
                 [
                   "email",
                   {},
                   "text",
                   "administrative.user@example.com"
                 ],
                 [
                   "tel",
                   {
                     "type": "voice"
                   },
                   "uri",
                   "tel:+1-555-555-1236;ext=789"
                 ],
                 [
                   "tel",
                   {
                     "type": "fax"
                   },
                   "uri",
                   "tel:+1-555-555-6321"
                 ]
               ]
             ]
           },
           {
             "objectClassName": "entity",
             "handle": "WWWW",
             "roles": [
               "billing"
             ],
             "vcardArray": [
               "vcard",
               [
                 [
                   "version",
                   {},
                   "text",
                   "4.0"
                 ],
                 [
                   "fn",
                   {},
                   "text",
                   "Billing User"
                 ],
                 [
                   "email",
                   {},
                   "text",
                   "billing.user@example.com"
                 ]
               ]
             ]
           }
         ],
         "events": [
           {
             "eventAction": "registration",
             "eventDate": "1997-06-03T00:00:00Z"
           },
           {
             "eventAction": "last changed",
             "eventDate": "2020-05-28T01:35:00Z"
           },
           {
             "eventAction": "expiration",
             "eventDate": "2021-06-03T04:00:00Z"
           }
         ],
         "status": [
           "server delete prohibited",
           "server update prohibited",
           "server transfer prohibited",
           "client transfer prohibited"
         ]
       }

                 Figure 11: Unredacted RDAP Lookup Response

   Example of the redacted version of an RDAP lookup response:

       {
         "rdapConformance": [
           "rdap_level_0",
           "redacted"
         ],
         "objectClassName": "domain",
         "ldhName": "example.com",
         "secureDNS": {
           "delegationSigned": false
         },
         "notices": [
           {
             "title": "Terms of Use",
             "description": [
               "Service subject to Terms of Use."
             ],
             "links": [
               {
                 "rel": "self",
                 "href": "https://www.example.com/terms-of-use",
                 "type": "text/html",
                 "value": "https://www.example.com/terms-of-use"
               }
             ]
           }
         ],
         "nameservers": [
           {
             "objectClassName": "nameserver",
             "ldhName": "ns1.example.com"
           },
           {
             "objectClassName": "nameserver",
             "ldhName": "ns2.example.com"
           }
         ],
         "entities": [
           {
             "objectClassName": "entity",
             "handle": "123",
             "roles": [
               "registrar"
             ],
             "publicIds": [
               {
                 "type": "IANA Registrar ID",
                 "identifier": "1"
               }
             ],
             "vcardArray": [
               "vcard",
               [
                 [
                   "version",
                   {},
                   "text",
                   "4.0"
                 ],
                 [
                   "fn",
                   {},
                   "text",
                   "Example Registrar Inc."
                 ],
                 [
                   "adr",
                   {},
                   "text",
                   [
                     "",
                     "Suite 100",
                     "123 Example Dr.",
                     "Dulles",
                     "VA",
                     "20166-6503",
                     "US"
                   ]
                 ],
                 [
                   "email",
                   {},
                   "text",
                   "contact@organization.example"
                 ],
                 [
                   "tel",
                   {
                     "type": "voice"
                   },
                   "uri",
                   "tel:+1.7035555555"
                 ],
                 [
                   "tel",
                   {
                     "type": "fax"
                   },
                   "uri",
                   "tel:+1.7035555556"
                 ]
               ]
             ],
             "entities": [
               {
                 "objectClassName": "entity",
                 "roles": [
                   "abuse"
                 ],
                 "vcardArray": [
                   "vcard",
                   [
                     [
                       "version",
                       {},
                       "text",
                       "4.0"
                     ],
                     [
                       "fn",
                       {},
                       "text",
                       "Abuse Contact"
                     ],
                     [
                       "email",
                       {},
                       "text",
                       "abuse@organization.example"
                     ],
                     [
                       "tel",
                       {
                         "type": "voice"
                       },
                       "uri",
                       "tel:+1.7035555555"
                     ]
                   ]
                 ]
               }
             ]
           },
           {
             "objectClassName": "entity",
             "handle": "XXXX",
             "roles": [
               "registrant"
             ],
             "vcardArray": [
               "vcard",
               [
                 [
                   "version",
                   {},
                   "text",
                   "4.0"
                 ],
                 [
                   "fn",
                   {},
                   "text",
                   ""
                 ],
                 [
                   "adr",
                   {},
                   "text",
                   [
                     "",
                     "",
                     "",
                     "",
                     "QC",
                     "",
                     "Canada"
                   ]
                 ]
               ]
             ]
           },
           {
             "objectClassName": "entity",
             "handle": "YYYY",
             "roles": [
               "technical"
             ],
             "vcardArray": [
               "vcard",
               [
                 [
                   "version",
                   {},
                   "text",
                   "4.0"
                 ],
                 [
                   "fn",
                   {},
                   "text",
                   ""
                 ],
                 [
                   "org",
                   {},
                   "text",
                   "Example Inc."
                 ],
                 [
                   "adr",
                   {},
                   "text",
                   [
                     "",
                     "Suite 1234",
                     "4321 Rue Somewhere",
                     "Quebec",
                     "QC",
                     "G1V 2M2",
                     "Canada"
                   ]
                 ]
               ]
             ]
           }
         ],
         "events": [
           {
             "eventAction": "registration",
             "eventDate": "1997-06-03T00:00:00Z"
           },
           {
             "eventAction": "last changed",
             "eventDate": "2020-05-28T01:35:00Z"
           },
           {
             "eventAction": "expiration",
             "eventDate": "2021-06-03T04:00:00Z"
           }
         ],
         "status": [
           "server delete prohibited",
           "server update prohibited",
           "server transfer prohibited",
           "client transfer prohibited"
         ],
         "redacted": [
           {
             "name": {
               "description": "Registry Domain ID"
             },
             "prePath": "$.handle",
             "pathLang": "jsonpath",
             "method": "removal",
             "reason": {
               "description": "Server policy"
             }
           },
           {
             "name": {
               "description": "Registrant Name"
             },
             "postPath": "$.entities[?(@.roles[0]=='registrant')].
               vcardArray[1][?(@[0]=='fn')][3]",
             "pathLang": "jsonpath",
             "method": "emptyValue",
             "reason": {
               "description": "Server policy"
             }
           },
           {
             "name": {
               "description": "Registrant Organization"
             },
             "prePath": "$.entities[?(@.roles[0]=='registrant')].
               vcardArray[1][?(@[0]=='org')]",
             "pathLang": "jsonpath",
             "method": "removal",
             "reason": {
               "description": "Server policy"
             }
           },
           {
             "name": {
               "description": "Registrant Street"
             },
             "postPath": "$.entities[?(@.roles[0]=='registrant')].
               vcardArray[1][?(@[0]=='adr')][3][:3]",
             "pathLang": "jsonpath",
             "method": "emptyValue",
             "reason": {
               "description": "Server policy"
             }
           },
           {
             "name": {
               "description": "Registrant City"
             },
             "postPath": "$.entities[?(@.roles[0]=='registrant')].
               vcardArray[1][?(@[0]=='adr')][3][3]",
             "pathLang": "jsonpath",
             "method": "emptyValue",
             "reason": {
               "description": "Server policy"
             }
           },
           {
             "name": {
               "description": "Registrant Postal Code"
             },
             "postPath": "$.entities[?(@.roles[0]=='registrant')].
               vcardArray[1][?(@[0]=='adr')][3][5]",
             "pathLang": "jsonpath",
             "method": "emptyValue",
             "reason": {
               "description": "Server policy"
             }
           },
           {
             "name": {
               "description": "Registrant Email"
             },
             "prePath": "$.entities[?(@.roles[0]=='registrant')].
               vcardArray[1][?(@[0]=='email')]",
             "method": "removal",
             "reason": {
               "description": "Server policy"
             }
           },
           {
             "name": {
               "description": "Registrant Phone"
             },
             "prePath": "$.entities[?(@.roles[0]=='registrant')].
               vcardArray[1][?(@[1].type=='voice')]",
             "method": "removal",
             "reason": {
               "description": "Server policy"
             }
           },
           {
             "name": {
               "description": "Technical Name"
             },
             "postPath": "$.entities[?(@.roles[0]=='technical')].
               vcardArray[1][?(@[0]=='fn')][3]",
             "method": "emptyValue",
             "reason": {
               "description": "Server policy"
             }
           },
           {
             "name": {
               "description": "Technical Email"
             },
             "prePath": "$.entities[?(@.roles[0]=='technical')].
               vcardArray[1][?(@[0]=='email')]",
             "method": "removal",
             "reason": {
               "description": "Server policy"
             }
           },
           {
             "name": {
               "description": "Technical Phone"
             },
             "prePath": "$.entities[?(@.roles[0]=='technical')].
               vcardArray[1][?(@[1].type=='voice')]",
             "method": "removal",
             "reason": {
               "description": "Server policy"
             }
           },
           {
             "name": {
               "description": "Technical Fax"
             },
             "prePath": "$.entities[?(@.roles[0]=='technical')].
               vcardArray[1][?(@[1].type=='fax')]",
             "reason": {
               "description": "Client request"
             }
           },
           {
             "name": {
               "description": "Administrative Contact"
             },
             "prePath": "$.entities[?(@.roles[0]=='administrative')]",
             "method": "removal",
             "reason": {
               "description": "Refer to the technical contact"
             }
           },
           {
             "name": {
               "description": "Billing Contact"
             },
             "prePath": "$.entities[?(@.roles[0]=='billing')]",
             "method": "removal",
             "reason": {
               "description": "Refer to the registrant contact"
             }
           }
         ]
       }

                  Figure 12: Redacted RDAP Lookup Response

   Example of the unredacted version of an RDAP search response:

     {
       "rdapConformance": [
         "rdap_level_0"
       ],
       "domainSearchResults":[
         {
           "objectClassName": "domain",
           "handle": "ABC121",
           "ldhName": "example1.com",
           "links":[
             {
               "value":"https://example.com/rdap/domain/example1.com",
               "rel":"self",
               "href":"https://example.com/rdap/domain/example1.com",
               "type":"application/rdap+json"
             },
             {
               "value":"https://example.com/rdap/domain/example1.com",
               "rel":"related",
               "href":"https://example.com/rdap/domain/example1.com",
               "type":"application/rdap+json"
             }
           ]
         },
         {
           "objectClassName": "domain",
           "handle": "ABC122",
           "ldhName": "example2.com",
           "links":[
             {
               "value":"https://example.com/rdap/domain/example2.com",
               "rel":"self",
               "href":"https://example.com/rdap/domain/example2.com",
               "type":"application/rdap+json"
             },
             {
               "value":"https://example.com/rdap/domain/example2.com",
               "rel":"related",
               "href":"https://example.com/rdap/domain/example2.com",
               "type":"application/rdap+json"
             }
           ]
         }
       ]
     }

                 Figure 13: Unredacted RDAP Search Response

   Example of the redacted version of an RDAP search response:

     {
       "rdapConformance": [
         "rdap_level_0",
         "redacted"
       ],
       "domainSearchResults":[
         {
           "objectClassName": "domain",
           "ldhName": "example1.com",
           "links":[
             {
               "value":"https://example.com/rdap/domain/example1.com",
               "rel":"self",
               "href":"https://example.com/rdap/domain/example1.com",
               "type":"application/rdap+json"
             },
             {
               "value":"https://example.com/rdap/domain/example1.com",
               "rel":"related",
               "href":"https://example.com/rdap/domain/example1.com",
               "type":"application/rdap+json"
             }
           ],
           "redacted": [
             {
               "name": {
                 "type": "Registry Domain ID"
               },
               "prePath": "$.domainSearchResults[0].handle",
               "pathLang": "jsonpath",
               "method": "removal",
               "reason": {
                 "type": "Server policy"
               }
             }
           ]
         },
         {
           "objectClassName": "domain",
           "ldhName": "example2.com",
           "links":[
             {
               "value":"https://example.com/rdap/domain/example2.com",
               "rel":"self",
               "href":"https://example.com/rdap/domain/example2.com",
               "type":"application/rdap+json"
             },
             {
               "value":"https://example.com/rdap/domain/example2.com",
               "rel":"related",
               "href":"https://example.com/rdap/domain/example2.com",
               "type":"application/rdap+json"
             }
           ],
           "redacted": [
             {
               "name": {
                 "description": "Registry Domain ID"
               },
               "prePath": "$.domainSearchResults[1].handle",
               "pathLang": "jsonpath",
               "method": "removal",
               "reason": {
                 "description": "Server policy"
               }
             }
           ]
         }
       ]
     }

                  Figure 14: Redacted RDAP Search Response

5.  JSONPath Considerations

   JSONPath [RFC9535] is the default JSON path expression language.
   This section includes JSONPath considerations for clients and
   servers.

5.1.  JSONPath Client Considerations

   This section covers considerations for clients that receive responses
   from servers using JSONPath [RFC9535] to identify redacted RDAP
   fields with the "prePath", "postPath", or "replacementPath" member of
   redacted objects in the "redacted" member.  The list of JSONPath
   client considerations include:

   1.  When the server is using the Redaction by Removal Method
       (Section 3.1) or the Redaction by Replacement Value Method
       (Section 3.4) with an alternative field value, the JSONPath
       expression of the "prePath" member will not resolve successfully
       with the redacted response.  The client can key off the "name"
       member for display logic related to the redaction.

5.2.  JSONPath Server Considerations

   This section covers considerations for servers using JSONPath
   [RFC9535] to identify redacted RDAP fields with the "prePath",
   "postPath", or "replacementPath" member of redacted objects in the
   "redacted" member.  The list of JSONPath considerations include:

   1.  Use absolute paths with the '$' JSONPath element.  An example is
       "$.handle" for the "Registry Domain ID" in a lookup response or
       "$.domainSearchResults[0].handle" in a search response.

   2.  Validate a JSONPath expression with the non-redacted RDAP
       response when using the "prePath" member, where evaluating the
       expression results in returning the redacted field.

   3.  Reference the removed object field when redacting an entire
       object by the Redaction by Removal Method (Section 3.1), where
       all of the object's child fields are explicitly removed.  An
       example is "$.entities[?(@.roles[0]=='administrative')]" for the
       entire "Administrative Contact".

   4.  Use multiple bases for the redaction of certain content.  For
       example, if server policy is such that all administrative-role
       entities are redacted and all technical-role entities are
       redacted, then an entity having both the administrative role and
       the technical role could be redacted for two different reasons.
       In this situation, a server is required to include at least one
       "redacted" entry, but it should consider including a separate
       "redacted" entry for each applicable basis for redaction to
       clearly document the server policies that are relevant to
       redaction in each instance.

   5.  Reference the removed field when using the Redaction by Removal
       Method (Section 3.1).  An example is "$.handle" for the "Registry
       Domain ID".

   6.  Reference index 0 of the jCard property array, which is the jCard
       "name" property, with a filter expression containing the name of
       the field when redacting a jCard field using the Redaction by
       Removal Method (Section 3.1).  An example is "$.entities[?(@.role
       s[0]=='registrant')].vcardArray[1][?(@[0]=='email')]" for the
       "Registrant Email".

   7.  Reference the jCard field value or values redacted by array index
       3 and greater when redacting a jCard field using the Redaction by
       Empty Value Method (Section 3.2).  The jCard property array index
       3 and greater contain the property values, where the property
       values set with an empty value are referenced directly in place
       of the jCard property name.  Servers can then systematically
       redact the jCard field value or values based on the JSONPath
       expressions, and clients will directly know which jCard property
       values have been redacted.  An example is "$.entities[?(@.roles[0
       ]=='registrant')].vcardArray[1][?(@[0]=='fn')][3]" for the
       "Registrant Name" or "$.entities[?(@.roles[0]=='registrant')].vca
       rdArray[1][?(@[0]=='adr')][3][5]" for the "Registrant Postal
       Code".

   8.  RDAP extensions should define any special JSONPath considerations
       required to identify redacted RDAP fields if these considerations
       are insufficient.

6.  IANA Considerations

6.1.  RDAP Extensions Registry

   IANA has registered the following value in the "RDAP Extensions"
   registry:

   Extension Identifier:  redacted

   Registry Operator:  Any

   Specification:  RFC 9537

   Contact:  IETF <iesg@ietf.org>

   Intended Usage:  This extension identifies the redacted fields in an
      RDAP response.

6.2.  RDAP JSON Values Registry

   Section 10.2 of [RFC9083] defines the "RDAP JSON Values" registry
   with predefined Type field values and a registration policy of Expert
   Review [RFC8126].  This specification defines three new Type field
   values that can be used to register predefined redacted name, reason,
   and expression language values.  IANA has updated the "RDAP JSON
   Values" registry to accept these additional Type field values as
   follows:

   "redacted name":  Redacted name being registered.  The registered
       redacted name is referenced using the "type" field of the
       redacted "name" field.

   "redacted reason":  Redacted reason being registered.  The registered
       redacted reason is referenced using the "type" field of the
       redacted "reason" field.

   "redacted expression language":  Redacted expression language being
       registered.  The registered redacted expression language is
       referenced using the "pathLang" field.

   IANA has also listed this document as a reference for the "RDAP JSON
   Values" registry and has registered the following value:

   Value:  jsonpath

   Type:  redacted expression language

   Description:  JSON path expression language, as defined in RFC 9535.

   Registrant:  IETF

   Contact Information:  iesg@ietf.org

   Reference:  RFC 9537

7.  Security Considerations

   The extension described in this document does not provide any
   security services beyond those described by [RFC9083].

8.  References

8.1.  Normative References

   [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>.

   [RFC6350]  Perreault, S., "vCard Format Specification", RFC 6350,
              DOI 10.17487/RFC6350, August 2011,
              <https://www.rfc-editor.org/info/rfc6350>.

   [RFC7095]  Kewisch, P., "jCard: The JSON Format for vCard", RFC 7095,
              DOI 10.17487/RFC7095, January 2014,
              <https://www.rfc-editor.org/info/rfc7095>.

   [RFC8126]  Cotton, M., Leiba, B., and T. Narten, "Guidelines for
              Writing an IANA Considerations Section in RFCs", BCP 26,
              RFC 8126, DOI 10.17487/RFC8126, June 2017,
              <https://www.rfc-editor.org/info/rfc8126>.

   [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>.

   [RFC8259]  Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
              Interchange Format", STD 90, RFC 8259,
              DOI 10.17487/RFC8259, December 2017,
              <https://www.rfc-editor.org/info/rfc8259>.

   [RFC9082]  Hollenbeck, S. and A. Newton, "Registration Data Access
              Protocol (RDAP) Query Format", STD 95, RFC 9082,
              DOI 10.17487/RFC9082, June 2021,
              <https://www.rfc-editor.org/info/rfc9082>.

   [RFC9083]  Hollenbeck, S. and A. Newton, "JSON Responses for the
              Registration Data Access Protocol (RDAP)", STD 95,
              RFC 9083, DOI 10.17487/RFC9083, June 2021,
              <https://www.rfc-editor.org/info/rfc9083>.

   [RFC9535]  Gössner, S., Ed., Normington, G., Ed., and C. Bormann,
              Ed., "JSONPath: Query Expressions for JSON", RFC 9535,
              DOI 10.17487/RFC9535, February 2024,
              <https://www.rfc-editor.org/info/rfc9535>.

8.2.  Informative References

   [RDAP-JSCONTACT]
              Loffredo, M. and G. Brown, "Using JSContact in
              Registration Data Access Protocol (RDAP) JSON Responses",
              Work in Progress, Internet-Draft, draft-ietf-regext-rdap-
              jscontact-17, 7 December 2023,
              <https://datatracker.ietf.org/doc/html/draft-ietf-regext-
              rdap-jscontact-17>.

Acknowledgements

   The authors wish to thank the following persons for their feedback
   and suggestions: Marc Blanchet, Tom Harrison, Scott Hollenbeck, Pawel
   Kowalik, Mario Loffredo, Gustavo Lozano, Andy Newton, Jasdip Singh,
   and Rick Wilhelm.

Authors' Addresses

   James Gould
   VeriSign, Inc.
   12061 Bluemont Way
   Reston, VA 20190
   United States of America
   Email: jgould@verisign.com
   URI:   http://www.verisign.com


   David Smith
   VeriSign, Inc.
   12061 Bluemont Way
   Reston, VA 20190
   United States of America
   Email: dsmith@verisign.com
   URI:   http://www.verisign.com


   Jody Kolker
   GoDaddy Inc.
   14455 N. Hayden Rd., #219
   Scottsdale, AZ 85260
   United States of America
   Email: jkolker@godaddy.com
   URI:   http://www.godaddy.com


   Roger Carney
   GoDaddy Inc.
   14455 N. Hayden Rd., #219
   Scottsdale, AZ 85260
   United States of America
   Email: rcarney@godaddy.com
   URI:   http://www.godaddy.com