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",
    "[email protected]"
  ]

     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",
                  "[email protected]"
                ],
                [
                  "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",
                      "[email protected]"
                    ],
                    [
                      "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",
                  "[email protected]"
                ],
                [
                  "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",
                  "[email protected]"
                ],
                [
                  "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",
                  "[email protected]"
                ],
                [
                  "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",
                  "[email protected]"
                ]
              ]
            ]
          }
        ],
        "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",
                  "[email protected]"
                ],
                [
                  "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",
                      "[email protected]"
                    ],
                    [
                      "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 <[email protected]>

  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:  [email protected]

  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: [email protected]
  URI:   http://www.verisign.com


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


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


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