M. Varley, Ed.
July 18, 2016

International Government Assurance Profile (iGov) for OpenID Connect 1.0
openid-igov-profile

Abstract

The OpenID Connect protocol defines an identity federation system that allows a relying party to request and receive authentication and profile information about an end user.

This specification profiles the OpenID Connect protocol to increase baseline security, provide greater interoperability, and structure deployments in a manner specifically applicable to (but not limited to) government and public service domains.


Table of Contents

1. Introduction

Government regulations for permitting users (citizens and non-citizens) online access to government resources vary greatly from region to region. There is a strong desire to leverage federated authentication and identity services for public access to government resources online to reduce 'password fatigue', increase overall account security, reduce cost, and provide reliable identity assurances from established and trusted sources when applicable.

This specification aims to define an OpenID Connect profile that provides governments with a foundation for securing federated access to public services online.

1.1. Requirements Notation and Conventions

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 RFC 2119 [RFC2119].

All uses of JSON Web Signature (JWS) [RFC7515] and JSON Web Encryption (JWE) [RFC7516] data structures in this specification utilize the JWS Compact Serialization or the JWE Compact Serialization; the JWS JSON Serialization and the JWE JSON Serialization are not used.

1.2. Terminology

This specification uses the terms "Access Token", "Authorization Code", "Authorization Endpoint", "Authorization Grant", "Authorization Server", "Client", "Client Authentication", "Client Identifier", "Client Secret", "Grant Type", "Protected Resource", "Redirection URI", "Refresh Token", "Resource Owner", "Resource Server", "Response Type", and "Token Endpoint" defined by OAuth 2.0 [RFC6749], the terms "Claim Name", "Claim Value", and "JSON Web Token (JWT)" defined by JSON Web Token (JWT) [RFC7519], and the terms defined by OpenID Connect Core 1.0 [OpenID.Core].

1.3. Conformance

** Given the wide range of government domains (local, regional, national) and interactions, what kind of conformance statement can we have here? **

2. Authorization Request

The following describes the supported OpenID Connect Authorization Code Flow parameters for use with iGov compatible IdPs.

Request Parameters:

client_id
REQUIRED. OAuth 2.0 Client Identifier valid at the Authorization Server.
response_type
REQUIRED. MUST be set to code.
acr_values
REQUIRED. Lists the acceptable LoAs for this authentication. See (below)
scope
REQUIRED. Indicates the attributes being requested. (See below)
redirect_uri
REQUIRED. Indicates a valid endpoint where the client will receive the authentication response. See (core section 3.1.2.1)
state
REQUIRED. Unguessable random string generated by the RP, used to protect against CSRF attacks. Must contain a sufficient amount of entropy to avoid guessing. Returned to the RP in the authentication response.
prompt
REQUIRED. This value must be set to select_account.
nonce
OPTIONAL. Unguessable random string generated by the client, used to protect against CSRF attacks. Must contain a sufficient amount of entropy to avoid guessing. Returned to the client in the ID Token.

A sample request may look like:

https://idp.government.gov/oidc/authorization?
  response_type=code
  &client_id=827937609728-m2mvqffo9bsefh4di90saus4n0diar2h
  &scope=d+openid
  &redirect_uri=https%3A%2F%2Frp.fed1.gov%2Foidc%2FloginResponse
  &state=2ca3359dfbfd0
  &prompt=select_account
  &acr_values=http%3A%2F%2Fidmanagement.gov%2Fns%2Fassurance%2Floa%2F1
+http%3A%2F%2Fidmanagement.gov%2Fns%2Fassurance%2Floa%2F2
+http%3A%2F%2Fidmanagement.gov%2Fns%2Fassurance%2Floa%2F3 
+http%3A%2F%2Fidmanagement.gov%2Fns%2Fa

3. Authorization Response

The following data will be sent as an Authorization Response to the Authorization Code Flow as desribed above. The authentication response is sent via HTTP redirect to the redirect URI specified in the request.

The following fields MUST be included in the response:

state
REQUIRED. The value of the state parameter passed in in the authentication request. This value MUST match exactly.
code
REQUIRED. The authorization code, a random string issued by the IdP to be used in the request to the token endpoint.

The following is an example response:

https://int-rp.fed1.securekey.com/skrp1/web/oidc/loginResponse?
    state=2ca3359dfbfd0
   &code=gOIFJ1hV6Rb1sxUdFhZGACWwR1sMhYbJJcQbVJN0wHA

4. Token Request

To retrieve the access and ID tokens, the client sends a token request to the token endpoint using HTTP POST with parameters in the form encoded body.

Clients must authenticate to the Token Endpoint using the client_secret_jwt or private_key_jwt method as described in (Core spec section 9).

The following parameters are specified:

grant_type
REQUIRED. MUST be set to authorization_code.
code
REQUIRED. The value of the code parameter returned in the authorization response.
client_assertion_type
REQUIRED. MUST be set to urn:ietf:params:oauth:client-assertion-type:jwt-bearer.
client_assertion
REQUIRED. The value of the signed client authentication JWT generated as described below. The RP must generate a new assertion JWT for each call to the token endpoint.

The signed client authentication token MUST contain the following parameters:

iss
REQUIRED. The client ID.
sub
REQUIRED. The client ID.
aud
REQUIRED. The URL of the token endpoint.
jti
REQUIRED. An unguessable random string generated by the client.
exp
REQUIRED. An integer timestamp (in Unix Epoch format) of the expiration of this assertion. This should be a very small time in the future, such as five minutes from issuance.

If the client is authenticating with the client_secret_jwt method, the client creates a JWS using an HMAC SHA algorithm, such as HMAC SHA-256. The HMAC (Hash-based Message Authentication Code) is calculated using the octets of the UTF-8 representation of the client_secret as the shared key. The server will have the same client_secret, and be able to verify the hash and therefore authenticate the client.

If the client is authenticating with the private_key_jwt method, the client signs this JWT with its own private key and sends it to the server as described above in the client_assertion field. Since the client has registered its public key, the server will be able to verify the signature of the JWT and therefore authenticate the client.

For example (with line wraps within values for display purposes only):

  POST /token HTTP/1.1
  Host: server.example.com
  Content-Type: application/x-www-form-urlencoded

  grant_type=authorization_code&
    code=i1WsRn1uB1&
    client_id=s6BhdRkqt3&
    client_assertion_type=
    urn%3Aietf%3Aparams%3Aoauth%3Aclient-assertion-type%3Ajwt-bearer&
    client_assertion=PHNhbWxwOl ... ZT
        

4.1. ID Tokens

The token response includes an access token (which can be used to make a UserInfo request) and ID token (a signed and optionally encrypted JSON Web Token). ID Token values have the following meanings:

iss
The "issuer" field is the Uniform Resource Locater (URL) of the expected issuer. MUST be verified by the client.
aud
The "audience" field contains the client ID of the client. MUST be verified by the client.
sub
The identifier of the user. SHOULD be a pairwize annonymous identifier, and be unique per client to prevent linkability and traceability between clients.
acr
The LoA the user was authenticated at. MUST be a member of the acr_values list from the authentication request.
nonce
The nonce value that was provided in the authentication request. Included if provided in authentication request.
jti
A unique identifier for the token, which can be used to prevent reuse of the token.
exp, iat, nbf
The "expiration", "issued at", and "not before" timestamps for the token are dates (integer number of seconds since from 1970-01-01T00:00:00Z UTC) within acceptable ranges

All ID Tokens MUST be signed by the OpenID Provider's private signature key. All clients MUST validate the signature of an ID Token before accepting it using the public key of the issuing server, which is published in JSON Web Key (JWK) [RFC7517] format. ID Tokens MAY be encrypted using the appropriate key of the requesting client.

The ID Token MUST expire and SHOULD have an active lifetime no longer than five minutes.

This example ID token has been signed using the server's RSA key:

eyJhbGciOiJSUzI1NiJ9.eyJhdXRoX3RpbWUiOjE0
  MTg2OTg3ODIsImV4cCI6MTQxODY5OTQxMiwic3ViI
  joiNldaUVBwblF4ViIsIm5vbmNlIjoiMTg4NjM3Yj
  NhZjE0YSIsImF1ZCI6WyJjMWJjODRlNC00N2VlLTR
  iNjQtYmI1Mi01Y2RhNmM4MWY3ODgiXSwiaXNzIjoi
  aHR0cHM6XC9cL2lkcC1wLmV4YW1wbGUuY29tXC8iL
  CJpYXQiOjE0MTg2OTg4MTJ9mQc0rtL56dnJ7_zO_f
  x8-qObsQhXcn-qN-FC3JIDBuNmP8i11LRA_sgh_om
  RRfQAUhZD5qTRPAKbLuCD451lf7ALAUwoGg8zAASI
  5QNGXoBVVn7buxPd2SElbSnHxu0o8ZsUZZwNpircW
  NUlYLje6APJf0kre9ztTj-5J1hRKFbbHodR2I1m5q
  8zQR0ql-FoFlOfPhvfurXxCRGqP1xpvLLBUi0JAw3
  F8hZt_i1RUYWMqLQZV4VU3eVNeIPAD38qD1fxTXGV
  Ed2XDJpmlcxjrWxzJ8fGfJrbsiHCzmCjflhv34O22
  zb0lJpC0d0VScqxXjNTa2-ULyCoehLcezmssg

Its claims are as follows:

 {
     "auth_time": 1418698782,
     "exp": 1418699412,
     "sub": "6WZQPpnQxV",
     "nonce": "188637b3af14a",
     "aud": [
        "c1bc84e4-47ee-4b64-bb52-5cda6c81f788"
     ],
     "iss": "https:\\/\\/idp-p.example.com\\/",
     "iat": 1418698812
  }
  

5. UserInfo Endpoint

Servers MUST support the UserInfo Endpoint and, at a minimum, the sub (subject) claim.

Support for a UserInfo Endpoint is important for maximum client implementation interoperability even if no additional user information is returned. Clients are not required to call the UserInfo Endpoint, but should not receive an error if they do.

In an example transaction, the client sends a request to the UserInfo Endpoint like the following:

GET /userinfo HTTP/1.1
Authorization: Bearer eyJhbGciOiJSUzI1NiJ9.eyJleHAiOjE0MTg3MDI0MTIsIm
F1ZCI6WyJjMWJjODRlNC00N2VlLTRiNjQtYmI1Mi01Y2RhNmM4MWY3ODgiXSwiaXNzIjo
iaHR0cHM6XC9cL2lkcC1wLmV4YW1wbGUuY29tXC8iLCJqdGkiOiJkM2Y3YjQ4Zi1iYzgx
LTQwZWMtYTE0MC05NzRhZjc0YzRkZTMiLCJpYXQiOjE0MTg2OTg4MTJ9i.HMz_tzZ90_b
0QZS-AXtQtvclZ7M4uDAs1WxCFxpgBfBanolW37X8h1ECrUJexbXMD6rrj_uuWEqPD738
oWRo0rOnoKJAgbF1GhXPAYnN5pZRygWSD1a6RcmN85SxUig0H0e7drmdmRkPQgbl2wMhu
-6h2Oqw-ize4dKmykN9UX_2drXrooSxpRZqFVYX8PkCvCCBuFy2O-HPRov_SwtJMk5qjU
WMyn2I4Nu2s-R20aCA-7T5dunr0iWCkLQnVnaXMfA22RlRiU87nl21zappYb1_EHF9ePy
q3Q353cDUY7vje8m2kKXYTgc_bUAYuW-W3SMSw5UlKaHtSZ6PQICoA
Accept: text/plain, application/json, application/*+json, */*
Host: idp-p.example.com
Connection: Keep-Alive
User-Agent: Apache-HttpClient/4.2.3 (java 1.5)

And receives a document in response like the following:

HTTP/1.1 200 OK
Date: Tue, 16 Dec 2014 03:00:12 GMT
Access-Control-Allow-Origin: *
Content-Type: application/json;charset=ISO-8859-1
Content-Language: en-US
Content-Length: 333
Connection: close

{
   "sub": "6WZQPpnQxV",
   "iss": "https://idp-p.example.com"
   "given_name": "Stephen",
   "family_name": "Emeritus",
}

Servers MUST support the generation of JWT [RFC7519] encoded responses from the UserInfo Endpoint in addition to unsigned JSON objects. Signed responses MUST be signed by the OpenID Provider's key, and encrypted responses MUST be encrypted with the authorized client's key. The OpenID Provider MUST support the RS256 signature method (the Rivest, Shamir, and Adleman (RSA) signature algorithm with a 256-bit hash) and MAY use other asymmetric signature and encryption methods listed in the JSON Web Algorithms (JWA [RFC7518]) specification.

6. Request Objects

Clients MAY optionally send requests to the authorization endpoint as signed or encrypted request objects using the request parameter as defined by OpenID Connect [OpenID.Core]. Servers MUST accept requests containing a request object signed by the client's private key. Servers MUST validate the signature on such requests against the client's registered public key. Clients must register their keys during client registration as described in the HEART OAuth 2.0 [HEART.OAuth2] profile. Servers MUST accept request objects encrypted with the server's public key.

Servers MAY accept request objects by reference using the request_uri parameter.

7. Authentication Context

OpenID Providers MUST provide acr (authentication context class reference, equivalent to the Security Assertion Markup Language (SAML) element of the same name) and amr (authentication methods reference) values in ID tokens.

It is recommended that both FICAM and eIDAS levels of assurance are supported in the authentication context by default.

Current NIST Levels of Assurance:

NIST Levels of Assurance
NIST LoA
http://idmanagement.gov/ns/assurance/loa/1
http://idmanagement.gov/ns/assurance/loa/2
http://idmanagement.gov/ns/assurance/loa/3

Current eIDAS Levels of Assurance:

eIDAS Levels of Assurance
eIDAS LoA
http://eidas.europa.eu/LoA/low
http://eidas.europa.eu/LoA/substantial
http://eidas.europa.eu/LoA/high

There is no requirement for authentication methods to be described in the Authentication Context as standards for levels of assurance should be outcome based. This also removes the requirement for RPs and IDPs to have a shared understanding of the authentication method values.

Note that OpenID Connect cannot provide LOA 4 identity assertions due to the way that the FICAM LOA values are currently defined.Proof-of-Possession Key Semantics for JWTs [RFC7800] may provide a mechanism to verify user keys.

The amr value is an array of strings describing the set of mechanisms used to authenticate the user to the OpenID Provider. Providers that require multi-factor authentication will typically provide multiple values (for example, memorized password plus hardware-token-generated one-time password). The specific values MUST be agreed upon and understood between the OpenID Provider and any Relying Parties.

In the future, this profile will likely reference and make use of the draft Vectors of Trust [I-D.richer-vectors-of-trust] standard.

8. Discovery

All OpenID Connect servers are uniquely identified by a URL known as the issuer. This URL serves as the prefix of a service discovery endpoint as specified in the OpenID Connect Discovery standard [OpenID.Discovery]. The discovery document MUST contain at minimum the following fields:

issuer
The fully qualified issuer URL of the server
authorization_endpoint
The fully qualified URL of the server's authorization endpoint defined by [RFC6749]
token_endpoint
The fully qualified URL of the server's token endpoint defined by [RFC6749]
introspection_endpoint
The fully qualified URL of the server's introspection endpoint defined by OAuth Token Introspection [RFC7662]
revocation_endpoint
The fully qualified URL of the server's revocation endpoint defined by OAuth Token Revocation [RFC7009]
jwks_uri
The fully qualified URI of the server's public key in JWK Set [RFC7517] format
scopes_supported
The list of iGov scopes the server supports
claims_supported
The list of claims available in the supported scopes. See below

8.1. Verifiable Claims

Some user data is particularly sensitive to exposure - Providers may have regulatory rules not to share the claim explicitly, and some federaitons may involve intermediaries that reprocess, repackage, or translate the claims before they are delivered to the client.

Providers may be able to provide a "verifiable" claim rather than the claim directly. Verifiable claims are cryptographically processed claims that can be verified by the client if they have the same claim data available and re-run the cryptographic process. The cryptographic algorithm SHOULD be a "proof-of-work" algoritm to present a sufficient deterant to brute force attacks on data sets which will have minimal entropy (such a 9 digit number).

Verifiable claims SHOULD be reserved for static data that has little or no formatting, for example: account numbers, phone numbers, document numbers, and so on. Data such as name or address are not appropriate for "verification" as the data format is highly variable.

For example: A client collects a national_id_no from a Provider, who has hashed the value using PBKDF2 with 1000 iterations. The client then must request the national_id_no directly from the user, and run the PBKDF2 algorithm with the same parameters. If the values match, then the user entered the same national_id_no that the Provider had on file.

Verifiable claims are declared in the Discovery claim by the Provider. The following additonal Discovery variables apply:

verifiable_claims
The list of supported_claims that will be returned as verifiable claims rather than plain text.
verifiable_claims_alg_supported
The supported algorithms for processing/verifying claims. (PBKDF2? bcrypt? scrypt?). Providers that include a user secret in the hash generation function MUST communicate that secret to their user out-of-band of the OpenID Connect flow, for example via email or SMS.

8.2. Example Discovery

The following example shows the JSON document found at a discovery endpoint for an authorization server:

{
  "request_parameter_supported": true,
  "id_token_encryption_alg_values_supported": [
    "RSA-OAEP", "RSA1_5", "RSA-OAEP-256"
  ],
  "registration_endpoint": "https://idp-p.example.com/register",
  "userinfo_signing_alg_values_supported": [
    "HS256", "HS384", "HS512", "RS256", "RS384", "RS512"
  ],
  "token_endpoint": "https://idp-p.example.com/token",
  "request_uri_parameter_supported": false,
  "request_object_encryption_enc_values_supported": [
    "A192CBC-HS384", "A192GCM", "A256CBC+HS512",
    "A128CBC+HS256", "A256CBC-HS512",
    "A128CBC-HS256", "A128GCM", "A256GCM"
  ],
  "token_endpoint_auth_methods_supported": [
    "private_key_jwt",
  ],
  "userinfo_encryption_alg_values_supported": [
    "RSA-OAEP", "RSA1_5",
    "RSA-OAEP-256"
  ],
  "subject_types_supported": [
    "public", "pairwise"
  ],
  "id_token_encryption_enc_values_supported": [
    "A192CBC-HS384", "A192GCM", "A256CBC+HS512",
    "A128CBC+HS256", "A256CBC-HS512", "A128CBC-HS256",
    "A128GCM", "A256GCM"
  ],
  "claims_parameter_supported": false,
  "jwks_uri": "https://idp-p.example.com/jwk",
  "id_token_signing_alg_values_supported": [
    "HS256", "HS384", "HS512", "RS256", "RS384", "RS512", "none"
  ],
  "authorization_endpoint": "https://idp-p.example.com/authorize",
  "require_request_uri_registration": false,
  "introspection_endpoint": "https://idp-p.example.com/introspect",
  "request_object_encryption_alg_values_supported": [
    "RSA-OAEP", ?RSA1_5", "RSA-OAEP-256"
  ],
  "service_documentation": "https://idp-p.example.com/about",
  "response_types_supported": [
    "code", "token"
  ],
  "token_endpoint_auth_signing_alg_values_supported": [
    "HS256", "HS384", "HS512", "RS256", "RS384", "RS512"
  ],
  "revocation_endpoint": "https://idp-p.example.com/revoke",
  "request_object_signing_alg_values_supported": [
    "HS256", "HS384", "HS512", "RS256", "RS384", "RS512"
  ],
  "claim_types_supported": [
    "normal"
  ],
  "grant_types_supported": [
    "authorization_code",
    "urn:ietf:params:oauth:grant-type:jwt-bearer",
  ],
  "scopes_supported": [
  ],
  "userinfo_endpoint": "https://idp-p.example.com/userinfo",
  "userinfo_encryption_enc_values_supported": [
    "A192CBC-HS384", "A192GCM", "A256CBC+HS512","A128CBC+HS256",
    "A256CBC-HS512", "A128CBC-HS256", "A128GCM", "A256GCM"
  ],
  "op_tos_uri": "https://idp-p.example.com/about",
  "issuer": "https://idp-p.example.com/",
  "op_policy_uri": "https://idp-p.example.com/about",
  "claims_supported": [
    "sub", "name", "given_name", "family_name",
    "middle_name", "nickname", "birthdate",
    "email", "email_verified", "phone_number", "address"
  ],

  "verifiable_claims" : [ "email", "phone_number" ],
  "verifiable_claims_alg_supported" : "bcrypt"
}

Clients and protected resources SHOULD cache this discovery information. It is RECOMMENDED that servers provide cache information through HTTP headers and make the cache valid for at least one week.

The server MUST provide its public key in JWK Set [RFC7517] format, such as the following 2048-bit RSA key:

{
  "keys": [
    {
      "alg": "RS256",
      "e": "AQAB",
      "n": "o80vbR0ZfMhjZWfqwPUGNkcIeUcweFyzB2S2T-hje83IOVct8gVg9FxvHPK1ReEW3-p7-A8GNcLAuFP_8jPhiL6LyJC3F10aV9KPQFF-w6Eq6VtpEgYSfzvFegNiPtpMWd7C43EDwjQ-GrXMVCLrBYxZC-P1ShyxVBOzeR_5MTC0JGiDTecr_2YT6o_3aE2SIJu4iNPgGh9MnyxdBo0Uf0TmrqEIabquXA1-V8iUihwfI8qjf3EujkYi7gXXelIo4_gipQYNjr4DBNlE0__RI0kDU-27mb6esswnP2WgHZQPsk779fTcNDBIcYgyLujlcUATEqfCaPDNp00J6AbY6w",
      "kty": "RSA",
      "kid": "rsa1"
    }
  ]
}

Clients and protected resources SHOULD cache this key. It is RECOMMENDED that servers provide cache information through HTTP headers and make the cache valid for at least one week.

9. User Info

The availability, quality, and reliability of an individual's identity attributes will vary greatly across jurisdictions and Provider systems. The following recommendations ensure maximum cross-jurisdictional interoperability, while setting Client expectations on the type of data they may acquire.

9.1. Claims Supported

Discovery mandates the inclusion of the claims_supported field that defines the claims a client MAY expect to receive for the supported scopes. Servers MUST return claims on a best effort basis. However, a server asserting it can provide a user claim does not imply that this data is available for all its users: clients MUST be prepared to receive partial data. Servers MAY return claims outside of the claims_supported list, but they MUST still ensure that the extra claims to not violate the privacy policies set out by the federation.

9.2. Scope Profiles

In the interests of data minimisation balanced with the requirement to successfully identity the individual signing in to a service the default OpenID Connect profiles may not be appropriate.

Matching of the identity assertion based on claims to a local identifier or ‘account’ related to the individual identity at a level of assurance is a requirement where the government in question is not able to provide a single identifier for all citizens based on an authoritative register of citizens.

The requirement for matching is also of importance where a cross-border or cross-jurisdiction authentication is required and therefore the availability of a single identifier (e.g. social security number) cannot be guaranteed for the individual wishing to authenticate.

This standard will define a set of common scope values that aim to provide maximum cross-jurisdictional identity matching while not being perscriptive on the exact attributes shared, as every jurisdiction will likely have varius levels of information available, and different policies for sharing personal data even if it is on file.

profile
The OpenID Connect Core [OpenID.Core] defined profile provides baseline identity information, such as name, current address, date of birth, etc... It is left to the Provider and the federation to set any limitations on this profile data - see Privacy Considerations.
document
The identity document type(s) and associated "number" the Provider is capable of providing. Mutliple document types MAY be returned. This could be passport, driver's license, national ID card, health insurance no., and so on. The response should include: type, number.
biometric
Biometric data related to the subject for verification at the client side. This can include simple descriptions for eye and hair color, height, or may include a photograph or some verifiable fingerprint/iris scan data.

9.3. Claims Metadata

Generally claims in OpenID Connect are self asserted, or the information about the claim is communicated out of band from the protocol. For example, a DMV providing a claim to a user's Driver's License number is considered an authoritative source of that attribute.

To support maximum interoperability and trust across (potentially) unassociated jurisdictions, the information regarding the claim type MUST be communicated within the protocol, so clients may properly interpret the claims they have been given. This is referred to as Claims Metadata.

The following defines the types of claims metadata that iGov supports:

locale
The locale format of the claim, indicating where the attribute originates from, represented as a space-separated list of BCP47 [RFC5646] language tag values: for example "en-US" or "ja" or "fr-CA" and so on.
encoding
How the claim is encoded: raw, jwt, hashed (hashed attributes are meant to allow the client to verify a value of a user's attribute without the server revealing what it has on file.)

9.3.1. Claim Level of Assurance

In addition to the scope of the data provided, the UserInfo data must return some concept of the quality level of the attribute. This quality level is refered to as attribute meta data, and follows the guidelines in Vectors of Trust [I-D.richer-vectors-of-trust].

The following must be considered when evaluating the quality of an attribute:

vot
The attribute Vector of Trust.
vtm
The Trustmark Provider URL for the vot claim.

9.4. Example UserInfo with Metadata

{
TODO example with metadata
}
  

10. Privacy Considerations

This section covers recommendations and guidelines for protecting a user's right to privacy in circumstances where this is required.

Government policies that protect an individual's right to privacy across jurisdictional boundires vary from geography to geography. Some geographies are looking to establish a global registry of basic citizen identity for digital use cases, and other geographies aim to supply only the bare minimum of an authentication assurances, ensuring participant systems cannot link or trace a citizen's actions across the federation. Most will fall somewhere in between these two extremes.

This specification supports this wide range of scenarios and therefore the following are NOT REQUIRED by Providers to implement, but HIGHLY RECOMMENDED for Providers that implement some level of user privacy.

11. Security Considerations

All transactions MUST be protected in transit by TLS as described in BCP195 [BCP195].

All clients MUST conform to applicable recommendations found in the Security Considerations sections of [RFC6749] and those found in the OAuth 2.0 Threat Model and Security Considerations document [RFC6819].

12. Normative References

[BCP195] Sheffer, Y., Holz, R. and P. Saint-Andre, "Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May 2015.
[HEART.OAuth2] Richer, J., "Health Relationship Trust Profile for OAuth 2.0", February 2016.
[I-D.ietf-oauth-pop-architecture] Hunt, P., Richer, J., Mills, W., Mishra, P. and H. Tschofenig, "OAuth 2.0 Proof-of-Possession (PoP) Security Architecture", Internet-Draft draft-ietf-oauth-pop-architecture-08, July 2016.
[I-D.richer-vectors-of-trust] Richer, J. and L. Johansson, "Vectors of Trust", Internet-Draft draft-richer-vectors-of-trust-04, January 2017.
[OpenID.Core] Sakimura, N., Bradley, J., Jones, M., de Medeiros, B. and C. Mortimore, "OpenID Connect Core 1.0", August 2015.
[OpenID.Discovery] Sakimura, N., Bradley, J., Jones, M. and E. Jay, "OpenID Connect Discovery 1.0", August 2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997.
[RFC2246] Dierks, T. and C. Allen, "The TLS Protocol Version 1.0", RFC 2246, DOI 10.17487/RFC2246, January 1999.
[RFC3986] Berners-Lee, T., Fielding, R. and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, DOI 10.17487/RFC3986, January 2005.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, DOI 10.17487/RFC5246, August 2008.
[RFC5322] Resnick, P., "Internet Message Format", RFC 5322, DOI 10.17487/RFC5322, October 2008.
[RFC5646] Phillips, A. and M. Davis, "Tags for Identifying Languages", BCP 47, RFC 5646, DOI 10.17487/RFC5646, September 2009.
[RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known Uniform Resource Identifiers (URIs)", RFC 5785, DOI 10.17487/RFC5785, April 2010.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and Verification of Domain-Based Application Service Identity within Internet Public Key Infrastructure Using X.509 (PKIX) Certificates in the Context of Transport Layer Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March 2011.
[RFC6749] Hardt, D., "The OAuth 2.0 Authorization Framework", RFC 6749, DOI 10.17487/RFC6749, October 2012.
[RFC6750] Jones, M. and D. Hardt, "The OAuth 2.0 Authorization Framework: Bearer Token Usage", RFC 6750, DOI 10.17487/RFC6750, October 2012.
[RFC6819] Lodderstedt, T., McGloin, M. and P. Hunt, "OAuth 2.0 Threat Model and Security Considerations", RFC 6819, DOI 10.17487/RFC6819, January 2013.
[RFC7009] Lodderstedt, T., Dronia, S. and M. Scurtescu, "OAuth 2.0 Token Revocation", RFC 7009, DOI 10.17487/RFC7009, August 2013.
[RFC7033] Jones, P., Salgueiro, G., Jones, M. and J. Smarr, "WebFinger", RFC 7033, DOI 10.17487/RFC7033, September 2013.
[RFC7515] Jones, M., Bradley, J. and N. Sakimura, "JSON Web Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May 2015.
[RFC7516] Jones, M. and J. Hildebrand, "JSON Web Encryption (JWE)", RFC 7516, DOI 10.17487/RFC7516, May 2015.
[RFC7517] Jones, M., "JSON Web Key (JWK)", RFC 7517, DOI 10.17487/RFC7517, May 2015.
[RFC7518] Jones, M., "JSON Web Algorithms (JWA)", RFC 7518, DOI 10.17487/RFC7518, May 2015.
[RFC7519] Jones, M., Bradley, J. and N. Sakimura, "JSON Web Token (JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015.
[RFC7662] Richer, J., "OAuth 2.0 Token Introspection", RFC 7662, DOI 10.17487/RFC7662, October 2015.
[RFC7800] Jones, M., Bradley, J. and H. Tschofenig, "Proof-of-Possession Key Semantics for JSON Web Tokens (JWTs)", RFC 7800, DOI 10.17487/RFC7800, April 2016.

Appendix A. Acknowledgements

The OpenID Community would like to thank the following people for their contributions to this specification: Justin Ritcher, Paul Grassi, John Bradley, Adam Cooper, ...

Appendix B. Notices

Copyright (c) 2015 The OpenID Foundation.

The OpenID Foundation (OIDF) grants to any Contributor, developer, implementer, or other interested party a non-exclusive, royalty free, worldwide copyright license to reproduce, prepare derivative works from, distribute, perform and display, this Implementers Draft or Final Specification solely for the purposes of (i) developing specifications, and (ii) implementing Implementers Drafts and Final Specifications based on such documents, provided that attribution be made to the OIDF as the source of the material, but that such attribution does not indicate an endorsement by the OIDF.

The technology described in this specification was made available from contributions from various sources, including members of the OpenID Foundation and others. Although the OpenID Foundation has taken steps to help ensure that the technology is available for distribution, it takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this specification or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any independent effort to identify any such rights. The OpenID Foundation and the contributors to this specification make no (and hereby expressly disclaim any) warranties (express, implied, or otherwise), including implied warranties of merchantability, non-infringement, fitness for a particular purpose, or title, related to this specification, and the entire risk as to implementing this specification is assumed by the implementer. The OpenID Intellectual Property Rights policy requires contributors to offer a patent promise not to assert certain patent claims against other contributors and against implementers. The OpenID Foundation invites any interested party to bring to its attention any copyrights, patents, patent applications, or other proprietary rights that may cover technology that may be required to practice this specification.

Appendix C. Document History

-2016-07-25

Author's Address

Michael Varley (editor) EMail: mike.varley@securekey.com