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Redacted Fields in the Registration Data Access Protocol (RDAP) Response
draft-ietf-regext-rdap-redacted-01

The information below is for an old version of the document.
Document Type
This is an older version of an Internet-Draft whose latest revision state is "Active".
Authors James Gould , David Smith , Jody Kolker , Roger Carney
Last updated 2021-09-01 (Latest revision 2021-08-30)
Replaces draft-gould-regext-rdap-redacted
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Submit for publication "Redacted Fields in the Registration Data Access Protocol (RDAP) Response"
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draft-ietf-regext-rdap-redacted-01
Network Working Group                                         J.G. Gould
Internet-Draft                                                D.S. Smith
Intended status: Standards Track                          VeriSign, Inc.
Expires: 5 March 2022                                        J.K. Kolker
                                                             R.C. Carney
                                                            GoDaddy Inc.
                                                        1 September 2021

Redacted Fields in the Registration Data Access Protocol (RDAP) Response
                   draft-ietf-regext-rdap-redacted-01

Abstract

   This document describes an RDAP extension for explicitly identifying
   redacted RDAP lookup response fields, using JSONPath as the default
   expression language.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 5 March 2022.

Copyright Notice

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

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents (https://trustee.ietf.org/
   license-info) in effect on the date of publication of this document.
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.  Code Components
   extracted from this document must include Simplified BSD License text
   as described in Section 4.e of the Trust Legal Provisions and are
   provided without warranty as described in the Simplified BSD License.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions Used in This Document . . . . . . . . . . . . . .   3
   3.  Redaction Methods . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  Redaction by Removal Method . . . . . . . . . . . . . . .   4
     3.2.  Redaction by Empty Value Method . . . . . . . . . . . . .   4
   4.  Redacted RDAP Response  . . . . . . . . . . . . . . . . . . .   5
     4.1.  RDAP Conformance  . . . . . . . . . . . . . . . . . . . .   5
     4.2.  "redacted" Member . . . . . . . . . . . . . . . . . . . .   6
   5.  JSONPath Considerations . . . . . . . . . . . . . . . . . . .  22
   6.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  23
     6.1.  RDAP Extensions Registry  . . . . . . . . . . . . . . . .  23
     6.2.  JSON Values Registry  . . . . . . . . . . . . . . . . . .  24
   7.  Security Considerations . . . . . . . . . . . . . . . . . . .  24
   8.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  24
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  24
     9.1.  Informative References  . . . . . . . . . . . . . . . . .  24
     9.2.  Normative References  . . . . . . . . . . . . . . . . . .  24
   Appendix A.  Change History . . . . . . . . . . . . . . . . . . .  26
     A.1.  Change from 00 to 01  . . . . . . . . . . . . . . . . . .  26
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  26

1.  Introduction

   This document describes an RDAP extension for explicitly identifying
   redacted RDAP lookup response fields, using JSONPath as the default
   expression language.  A redacted RDAP field is one that has data
   removed from the RDAP lookup response due to 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
   [RFC7483], or RDAP fields defined in RDAP extensions.  Because an
   RDAP lookup response may exclude a field due to either the lack of
   data or based on the lack of RDAP client privileges, this extension
   is used to explicitly specify which RDAP fields are not included in
   the RDAP lookup response due to redaction.  It thereby provides a
   capability for disambiguation between redaction and possible other
   reasons for data or field absence.

   In [RFC7482] 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 in a lookup response.

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   JSONPath, as defined in [I-D.ietf-jsonpath-base], is used as the
   default expression language to reference RDAP fields that have been
   redacted.  The redacted JSON fields will either be removed or have
   empty values in the RDAP lookup 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 whitespace.  For
   instance, the JSONPath expressions are broken out into multiple lines
   when required for illustration.

3.  Redaction Methods

   Redaction in RDAP can be handled in multiple ways.  The use of
   placeholder text for the values of the RDAP fields, such as the
   placeholder text "XXXX", MUST NOT be used for redaction.  A
   placeholder text value will not match the format requirements of each
   of the RDAP fields and provides 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 [RFC7483], include a mix of JSON
   objects and JSON arrays, where JSON arrays are heavily used for
   entity objects with jCard [RFC7095].  jCard [RFC7095] is a JSON
   representation of vCard [RFC6350] that inherits its dependency on
   arrays.  An example is the vCard [RFC6350] "ADR" property / jCard
   [RFC7095] "adr" property that 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 [RFC7095] 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 two categories of
   Redaction by Removal Method (Section 3.1) and Redaction by Empty
   Value Method (Section 3.2), defined in the following sub-sections.

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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 preferred method.  The Redaction
   by Removal Method can be done for all RDAP response fields other than
   response fields using the position in an array to signal the redacted
   field (e.g., the JSON arrays used with jCard [RFC7095]).  RDAP
   extensions such as JSContact in Registration Data Access Protocol
   (RDAP) JSON Responses [I-D.ietf-regext-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": {
         "type": "Administrative Contact"
       },
       "path": "$.entities[?(@.roles[0]=='administrative')]",
       "method": "removal"
     }
   ]

   The Redaction by Removal Method MUST NOT be used to remove a field
   using the position in a fixed length array to signal the redacted
   field.  For example, removal of an individual data field in jCard
   [RFC7095] will result in a non-conformant jCard [RFC7095] 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 [RFC7095] Text ("text") property or null for non-Text ("text")
   properties.  The empty jCard [RFC7095] values ("" or null) are
   referenced in the "redacted" member in place of the jCard [RFC7095]
   property name, 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 SHOULD be used only
   when redacting JSON response fields that use the position in an array
   to signal the redacted field (e.g., jCard [RFC7095] arrays).
   Optional jCard [RFC7095] properties SHOULD use the Redaction by

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   Removal Method (Section 3.1) to redact the entire property.  The
   required jCard [RFC7095] "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 [RFC7095].

   An example of the redacted field "fn" jCard property using the
   Redaction by Empty Value Method:

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

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

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

4.  Redacted RDAP Response

4.1.  RDAP Conformance

   RDAP lookup responses that contain values described in this document
   MUST indicate conformance with this specification by including an
   rdapConformance ([RFC7483]) value of "redacted_0.1".  The information
   needed to register this value in the RDAP Extensions Registry is
   described in Section 6.1.

   Example rdapConformance member with the redacted extension:

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   "rdapConformance": [
     "rdap_level_0",
     "redacted_0"
   ]

4.2.  "redacted" Member

   The "redacted" member MUST be added to the RDAP lookup response when
   there are redacted fields.  The "redacted" member contains an array
   of redacted objects with the following child members:

   "name":  A 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.

   "path":  The JSON expression of the redacted field, using the
       expression language defined by the "pathLang" member.  The JSON
       expression references a removed JSON field or an empty field
       value based on Section 3.

   "pathLang":  OPTIONAL JSON path expression language used, with the
       default value of "jsonpath" for JSONPath
       ([I-D.ietf-jsonpath-base]).  Other JSON path expression languages
       MAY be used based on server policy.

   "method":  OPTIONAL redaction method used with "removal" indicating
       the Redaction By Removed Method (Section 3.1) and "emptyValue"
       indicating the Redaction by Empty Value Method (Section 3.2),
       with the default value of "removal".

   "reason":  OPTIONAL human readable reason(s) for the redacted field
       in the language defined by the [RFC7483] "lang" member.  The
       default language is "en" if the [RFC7483] "lang" member is not
       specified.  The reason is defined using an object with an
       OPTIONAL "type" field denoting a registered redacted reason (see
       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 unredacted version of RDAP lookup response:

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     {
       "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"
             }

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           ],
           "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"

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                 },
                 "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"
                   ]
                 ]
               ]
             }
           ]
         },
         {
           "roles": [

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             "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"
                 },

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                 "uri",
                 "tel:+1-555-555-1235;ext=123"
               ],
               [
                 "tel",
                 {
                   "type": "fax"
                 },
                 "uri",
                 "tel:+1-555-555-5321"
               ]
             ]
           ]
         },
         {
           "roles": [
             "technical"
           ],
           "vcardArray": [
             "vcard",
             [
               [
                 "version",
                 {},
                 "text",
                 "4.0"
               ],
               [
                 "fn",
                 {},
                 "text",
                 "Technical User"
               ],
               [
                 "org",
                 {},
                 "text",
                 "Example Inc."
               ],
               [
                 "adr",
                 {},
                 "text",
                 [
                   "",
                   "Suite 1234",
                   "4321 Rue Somewhere",
                   "Quebec",

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                   "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"
               ]
             ]
           ]
         },
         {
           "roles": [
             "administrative"
           ],
           "vcardArray": [
             "vcard",
             [
               [
                 "version",
                 {},
                 "text",
                 "4.0"
               ],
               [
                 "fn",
                 {},
                 "text",
                 "Administrative User"

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               ],
               [
                 "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"
               ]
             ]
           ]
         }
       ],
       "events": [

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         {
           "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"
       ]
     }

   Example redacted version of RDAP response:

     {
       "rdapConformance": [
         "rdap_level_0",
         "redacted_0"
       ],
       "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"
             }
           ]
         }

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       ],
       "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",

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                   "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",

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                     "Abuse Contact"
                   ],
                   [
                     "email",
                     {},
                     "text",
                     "abuse@organization.example"
                   ],
                   [
                     "tel",
                     {
                       "type": "voice"
                     },
                     "uri",
                     "tel:+1.7035555555"
                   ]
                 ]
               ]
             }
           ]
         },
         {
           "roles": [
             "registrant"
           ],
           "vcardArray": [
             "vcard",
             [
               [
                 "version",
                 {},
                 "text",
                 "4.0"
               ],
               [
                 "fn",
                 {},
                 "text",
                 ""
               ],
               [
                 "adr",
                 {},
                 "text",
                 [
                   "",
                   "",
                   "",

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                   "",
                   "QC",
                   "",
                   "Canada"
                 ]
               ]
             ]
           ]
         },
         {
           "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"
                 ]
               ]

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             ]
           ]
         }
       ],
       "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": {
             "type": "Registry Domain ID"
           },
           "path": "$.handle",
           "pathLang": "jsonpath",
           "method": "removal",
           "reason": {
             "type": "Server policy"
           }
         },
         {
           "name": {
             "type": "Registrant Name"
           },
           "path": "$.entities[?(@.roles[0]=='registrant')].
             vcardArray[1][?(@[0]=='fn')][3]",
           "pathLang": "jsonpath",
           "method": "emptyValue",
           "reason": {
             "type": "Server policy"
           }
         },

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         {
           "name": {
             "type": "Registrant Organization"
           },
           "path": "$.entities[?(@.roles[0]=='registrant')].
             vcardArray[1][?(@[0]=='org')]",
           "pathLang": "jsonpath",
           "method": "removal",
           "reason": {
             "type": "Server policy"
           }
         },
         {
           "name": {
             "type": "Registrant Street"
           },
           "path": "$.entities[?(@.roles[0]=='registrant')].
             vcardArray[1][?(@[0]=='adr')][3][:3]",
           "pathLang": "jsonpath",
           "method": "emptyValue",
           "reason": {
             "type": "Server policy"
           }
         },
         {
           "name": {
             "type": "Registrant City"
           },
           "path": "$.entities[?(@.roles[0]=='registrant')].
             vcardArray[1][?(@[0]=='adr')][3][3]",
           "pathLang": "jsonpath",
           "method": "emptyValue",
           "reason": {
             "type": "Server policy"
           }
         },
         {
           "name": {
             "type": "Registrant Postal Code"
           },
           "path": "$.entities[?(@.roles[0]=='registrant')].
             vcardArray[1][?(@[0]=='adr')][3][5]",
           "pathLang": "jsonpath",
           "method": "emptyValue",
           "reason": {
             "type": "Server policy"
           }
         },

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         {
           "name": {
             "type": "Registrant Email"
           },
           "path": "$.entities[?(@.roles[0]=='registrant')].
             vcardArray[1][?(@[0]=='email')]",
           "method": "removal",
           "reason": {
             "type": "Server policy"
           }
         },
         {
           "name": {
             "type": "Registrant Phone"
           },
           "path": "$.entities[?(@.roles[0]=='registrant')].
             vcardArray[1][?(@[1].type=='voice')]",
           "method": "removal",
           "reason": {
             "type": "Server policy"
           }
         },
         {
           "name": {
             "type": "Technical Name"
           },
           "path": "$.entities[?(@.roles[0]=='technical')].
             vcardArray[1][?(@[0]=='fn')][3]",
           "method": "emptyValue",
           "reason": {
             "type": "Server policy"
           }
         },
         {
           "name": {
             "type": "Technical Email"
           },
           "path": "$.entities[?(@.roles[0]=='technical')].
             vcardArray[1][?(@[0]=='email')]",
           "method": "removal",
           "reason": {
             "type": "Server policy"
           }
         },
         {
           "name": {
             "type": "Technical Phone"
           },

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           "path": "$.entities[?(@.roles[0]=='technical')].
             vcardArray[1][?(@[1].type=='voice')]",
           "method": "removal",
           "reason": {
             "type": "Server policy"
           }
         },
         {
           "name": {
             "description": "Technical Fax"
           },
           "path": "$.entities[?(@.roles[0]=='technical')].
             vcardArray[1][?(@[1].type=='fax')]",
           "reason": {
             "type": "Client request",
             "description": "Client requested the field redacted"
           }
         },
         {
           "name": {
             "type": "Administrative Contact"
           },
           "path": "$.entities[?(@.roles[0]=='administrative')]",
           "method": "removal",
           "reason": {
             "description": "Refer to the technical contact"
           }
         }
       ]
     }

5.  JSONPath Considerations

   JSONPath [I-D.ietf-jsonpath-base] is the default JSON path expression
   language.  This section covers considerations for servers using
   [I-D.ietf-jsonpath-base] to identify redacted RDAP fields with the
   "path" 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".
   2.  Validate a JSONPath expression using a non-redacted RDAP lookup
       response, where evaluating the expression results in returning
       the redacted field.

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   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 "$.entities[?(@.roles[0]=='administrative')]" for the
       entire "Administrative Contact".
   4.  When an entity has multiple roles, include "redacted" members for
       each role using the role index.  This will result in duplicate
       "redacted" members, but will enable the client to treat redaction
       consistently when there is a single role per entity or multiple
       roles per entity.  An example is when the "roles" member has the
       value '["registrant","administrative"]', redacting the "name"
       member of the entity will result in two "redacted" members with
       the JSONPath expressions "$.entities[?(@.roles[0]=='registrant')]
       .vcardArray[1][?(@[0]=='fn')][3]" and "$.entities[?(@.roles[1]=='
       administrative')].vcardArray[1][?(@[0]=='fn')][3]".
   5.  Reference the removed field when using the Redaction by Removal
       Method (Section 3.1).  An example is "$.handle" for the "Registry
       Domain ID".
   6.  Reference index 0 of the jCard [RFC7095] property array, which is
       the jCard [RFC7095] "name" property, with a filter expression
       containing the name of the field, when redacting a jCard
       [RFC7095] field using the Redaction by Removal Method
       (Section 3.1).  An example is "$.entities[?(@.roles[0]=='registra
       nt')].vcardArray[1][?(@[0]=='email')]" for the "Registrant
       Email".
   7.  Reference jCard [RFC7095] field value or values redacted by array
       index 3 and greater, when redacting a jCard [RFC7095] field using
       the Redaction by Empty Value Method (Section 3.2).  The jCard
       [RFC7095] property array index 3 and greater contain the property
       values, where the property values set with an empty value are
       referenced directly in place of the jCard [RFC7095] property
       name.  Servers can then systematically redact jCard [RFC7095]
       field value or values based on the JSONPath expressions and
       clients will directly know which jCard [RFC7095] property values
       have been redacted.  An example is "$.entities[?(@.roles[0]=='reg
       istrant')].vcardArray[1][?(@[0]=='fn')][3]" for the "Registrant
       Name" or "$.entities[?(@.roles[0]=='registrant')].vcardArray[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 is requested to register the following value in the RDAP
   Extensions Registry:

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   Extension identifier:  redacted_0.1
   Registry operator:  Any
   Published specification:  This document.
   Contact:  IESG <iesg@ietf.org>
   Intended usage:  This extension identifies the redacted fields in an
      RDAP lookup response.

6.2.  JSON Values Registry

   Section 10.2 of [RFC9083] defines the JSON Values Registry with pre-
   defined Type field values and the use of the "Expert Review" policy
   defined in [RFC8126].  Two new JSON Values Registry Type field values
   are used to register pre-defined redacted name and reason values:

   "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.

7.  Security Considerations

   The server including a redacted signal provides an unauthorized
   client additional information related to the existence of data.
   Servers MAY exclude the redacted members for RDAP fields that are
   considered a privacy issue in providing a data existence signal.

8.  Acknowledgements

   The authors wish to thank the following persons for their feedback
   and suggestions: Marc Blanchet, Scott Hollenbeck, Mario Loffredo,
   Gustavo Lozano, and Rick Wilhelm.

9.  References

9.1.  Informative References

   [I-D.ietf-regext-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-02, 28 May 2021, <https://tools.ietf.org/html/
              draft-ietf-regext-rdap-jscontact-02>.

9.2.  Normative References

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   [I-D.ietf-jsonpath-base]
              Gössner, S., Normington, G., and C. Bormann, "JSONPath:
              Query expressions for JSON", Work in Progress, Internet-
              Draft, draft-ietf-jsonpath-base-01, 8 July 2021,
              <https://tools.ietf.org/html/draft-ietf-jsonpath-base-01>.

   [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>.

   [RFC7482]  Newton, A. and S. Hollenbeck, "Registration Data Access
              Protocol (RDAP) Query Format", RFC 7482,
              DOI 10.17487/RFC7482, March 2015,
              <https://www.rfc-editor.org/info/rfc7482>.

   [RFC7483]  Newton, A. and S. Hollenbeck, "JSON Responses for the
              Registration Data Access Protocol (RDAP)", RFC 7483,
              DOI 10.17487/RFC7483, March 2015,
              <https://www.rfc-editor.org/info/rfc7483>.

   [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>.

   [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>.

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Appendix A.  Change History

A.1.  Change from 00 to 01

   1.  Changed rdapConformance to use pointed "redacted_0.1" value to
       support structural changes of the extension up to the target of
       "redacted_1.0".
   2.  Updates based on the Gustavo Lozano feedback:
       1.  Updated the language to change the special treatment of jCard
           to be more generic for future RDAP extensions that leverage
           fixed length JSON arrays.
       2.  Added "RDAP extensions should define any special JSONPath
           considerations required to identify redacted RDAP fields if
           the these considerations are insufficient." to the JSONPath
           Considerations section to generalize it.
   3.  Updates based on the Marc Blanchet feedback:
       1.  Added a reference to draft-ietf-regext-rdap-jscontact as an
           example of an RDAP extension that is suited for the Redaction
           by Removal Method based on the lack of dependency on
           positional JSON arrays.
       2.  Added support for registered and unregistered (free-form)
           redaction reasons by changing the "reason" property to be a
           JSON object with the "type" and "description" properties.
           The "type" property includes registration in the IANA JSON
           Values Registry.
       3.  Added a "JSON Values Registry" section in the IANA
           Considersations section to define the "redaction reason" JSON
           Values Registry Type values to support the registration of
           redaction reasons.
   4.  Updates based on the Mario Loffredo feedback:
       1.  Added support for registered and unregistered (free-form)
           redaction names by changing the "reason" property to be a
           JSON object with the "type" and "description" properties.
           The "type" property includes registration in the IANA JSON
           Values Registry.
       2.  Added a "JSON Values Registry" section in the IANA
           Considersations section to define the "redaction name" JSON
           Values Registry Type values to support the registration of
           redaction names.
       3.  Added a JSONPath Considerations item associated with handling
           entities with multiple roles.
       4.  Added language to restrict the extension to lookup responses.

Authors' Addresses

   James Gould
   VeriSign, Inc.
   12061 Bluemont Way

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   Reston, VA 20190
   United States of America

   Email: jgould@verisign.com
   URI:   http://www.verisigninc.com

   David Smith
   VeriSign, Inc.
   12061 Bluemont Way
   Reston, VA 20190
   United States of America

   Email: dsmith@verisign.com
   URI:   http://www.verisigninc.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

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