PingAM 8.0.0

Authentication requirements

A relying party (RP) can have different authentication requirements for different protected resources. For example, a financial services provider accepts username and password authentication to create an account, but requires multi-factor authentication to download bank account statements.

AM lets you associate requirements with authentication journeys. RPs specify the authentication requirements in their requests, and AM uses the associations to authenticate the end user with the requested journey and honor the requirements.

AM communicates the honored requirements by optionally returning claims in ID tokens. It uses the following standard claims:

  • An authentication context class reference (acr) claim holds a case-sensitive string identifying the class of authentication methods or procedures the authentication process satisfied. For example, an identifier for the authentication journey the end user completed successfully.

  • An authentication method references (amr) claim holds a JSON array of strings identifying the authentication methods satisfied. For example, an indication the end user has authenticated with a username-password combination and a one-time password.

The acr claim

The acr claim holds a case-sensitive string you configure in the OAuth 2.0 provider service. AM maps acr keys to authentication journeys to avoid directly exposing the journey names.

AM doesn’t add the acr claim to ID tokens by default. The RP must request authentication contexts and AM must authenticate the end user.

The acr claims can be voluntary or essential.

Voluntary claims

RPs request voluntary acr claims for optional authentication mechanisms to improve the user experience. They do this in one of the following ways:

  • Specify the authentication mechanism in the acr_values parameter for a request to the /oauth2/authorize endpoint.

  • Specify the authentication mechanisms in the JSON format claims parameter for a request to the /oauth2/authorize endpoint.

  • Rather than specifying the mechanisms in the request, rely on Default ACR values in the RP client profile.

    Find the field in the AM admin UI under Realms > Realm Name > Applications > OAuth 2.0 > Client ID > OpenID Connect.

    The default acr values are the keys of the mapping set when you Configure acr claims. The JSON response from the /oauth2/.well-known/openid-configuration endpoint lists the keys as acr_values_supported strings; for example:

    "acr_values_supported": ["username-password"]

    Any mechanisms the RP specifies in the request override the default acr values.

Essential claims

RPs request essential acr claims for required authentication mechanisms.

RPs request essential acr claims by specifying the authentication mechanisms in the JSON format claims parameter for a request to the /oauth2/authorize endpoint.

Essential claims resemble, but are unrelated to, step-up authentication.

Configure acr claims

  1. In the AM admin UI, go to Realms > Realm Name > Services > OAuth2 Provider > Advanced OpenID Connect.

  2. Enable Enable "claims_parameter_supported" to let RPs request acr claims using the claims parameter.

  3. In the OpenID Connect acr_values to Auth Chain Mapping box, map keys to authentication journey identifiers.

    The following example maps username-password to the Login journey:

    Map `acr` claim strings to journeys.

    The acr-key mapped to the journey AM uses to authenticate the end user becomes the value of the acr claim in the resulting ID token.

  4. Save your changes.

Request processing

When an RP requests authentication contexts, AM initially determines the requested journey. It uses the first context for which it has a valid mapping. For example, if the RP requests push otp username-password and AM has mappings only for otp and username-password, AM chooses otp to authenticate the end user.

The following table describes how AM processes the request:

Scenario Voluntary claims result Essential claims result

The end user isn’t authenticated.

Authenticate with the requested journey.

Authenticate with the requested journey.

The end user is authenticated with the requested journey.

Don’t reauthenticate.

Reauthenticate with the requested journey.

On success, delete the original session and create a new session.

The end user is authenticated with a different journey.

Reauthenticate with the requested journey.

On success, delete the original session and create a new session.

The request specifies an unmapped acr_values or claims string.

Continue the grant flow without returning an error.

Return an error and redirect to the redirect_uri, if available.

After authenticating the end user, AM returns an ID token whose acr claim has one of the following values:

0 (zero)

The RP requested an unmapped voluntary claim.

acr-key

The end user authenticated with the journey mapped to the acr-key.

If authentication involves more than one journey, the acr-key reflects the last mapped journey.

The amr claim

The amr claim holds an array of strings identifying families of authentication methods.

You can map an amr session property to amr values using the Set Session Properties node. Then update the user info claims script to retrieve the amr values mapped to the amr session property.

When the end user authenticates with a journey using the node, AM includes the amr claim in the ID token it issues.

Configure amr claims

Configure an authentication journey

  1. Update an authentication journey to include the Set Session Properties node, for example, update the acr claims journey.

  2. On the Set Session Properties node, configure a key to identify the amr values, for example amr.

    As its value, enter a string to identify the authentication method satisfied. For example, otp.

    Example: Configure the amr session property
    amr-set-session-properties

  3. Save your changes.

Configure the user info claims script

This task describes how to modify the default user info claims script to retrieve the amr values mapped to the amr session property.

To create a new script instead, refer to Manage scripts (UI), and reference the new script name when you configure the provider.

  1. In the AM admin UI, go to Realms > Realm Name > Scripts, and click OIDC Claims Script.

  2. In the Script field:

    • Groovy

    • JavaScript

    Add the amr claim details after the existing computedClaims line. For example:

    computedClaims = claimsToResolve.collectEntries() { claim ->
    result = computeClaim(claim)
}

if (session != null) {
  def amrValues = [session.getProperty("amr")];
  computedClaims.put("amr", amrValues)
}

    Add the amr claim details before the return computedClaims; line. For example:

    if (session !== null && session !== undefined) {
  var amrValues = [session.getProperty("amr")];
  computedClaims.put("amr", amrValues)
}

return computedClaims;

  3. Save your changes.

The default user info claims script is now amended to retrieve amr values mapped to the amr session property.

Allowlist the session property

Provide access to the amr session property to allow it to be output in the ID token.

  1. In the AM admin UI, go to Realms > Realm Name > Services > Session Property Whitelist Service.

  2. Add amr to the Allowlisted Session Property Names field.

  3. Save your changes.

Configure AM to use the user info claims script

Perform this task to set up an OAuth2 provider to use your custom script.

  1. Configure the provider and ensure the following properties are set:

    • OIDC Claims Plugin Type to SCRIPTED.

    • OIDC Claims Script to OIDC Claims Script.

    If you created a new script rather than editing the default, reference the new script name here.

  2. Save your changes.

Configure the provider to return claims in the ID token

Perform this task to configure the OAuth2 provider to always return scope-derived claims in the ID token.

This option is disabled by default because of the security concerns of returning claims that may contain sensitive user information. Learn more in Request claims in ID tokens.

  1. In the AM admin UI, go to Realms > Realm Name > Services > OAuth2 Provider > Advanced OpenID Connect.

  2. Select Always Return Claims in ID Tokens.

  3. Save your changes.

Demonstrate authentication requirements

Demonstrate the process with an RP that uses the Implicit grant:

  1. Create an end user profile and record the username and password.

  2. Create an RP profile.

  3. Duplicate the default Example journey to create a Login journey.

  4. Optionally configure amr claims.

  5. Configure acr claims to map your duplicate journey to the username-password claim.

  6. Request voluntary claims.

  7. Request essential claims.

Create an RP profile

Register an OIDC application with the following settings:

Setting Value

Name

myClient

Redirection URIs

https://www.example.com:443/callback

Scopes

openid
profile

Advanced > Grant Types

Add Implicit

Request voluntary claims

  1. Open a new tab in your browser.

  2. Paste a URL with the acr_values parameter to request voluntary claims into the new browser tab.

    The following URL requests an ID token with the implicit grant:

    https://am.example.com:8443/am/oauth2/realms/root/realms/alpha/authorize?acr_values=username-password&client_id=myClient&response_type=id_token&scope=openid%20profile&redirect_uri=https://www.example.com:443/callback&nonce=abc123&state=123abc

  3. Authenticate as the end user.

    AM redirects to the application sign-in URL (redirect_uri) with the id_token in the fragment.

  4. Extract the ID token from the sign-in URL.

  5. Decode the ID token to display the acr claim:

    {
  "...": "...",
  "acr": "username-password"
}

    The amr claim is also displayed in the decoded token if you configured amr claims, for example:

      "amr": [
    "otp"
  ],

Request essential claims

  1. Define and URL-encode the essential claims parameter value.

    Essential claims requesting username-password:

      {"id_token":{"acr":{"essential":true,"values":["username-password"]}}}

    URL-encoded value:

    %7B%22id_token%22%3A%7B%22acr%22%3A%7B%22essential%22%3Atrue%2C%22values%22%3A%5B%22username-password%22%5D%7D%7D%7D

  2. Paste a URL with the encoded claims parameter to request essential claims into the new browser tab.

    The following URL requests an ID token with the implicit grant:

    https://am.example.com:8443/am/oauth2/realms/root/realms/alpha/authorize?claims=%7B%22id_token%22%3A%7B%22acr%22%3A%7B%22essential%22%3Atrue%2C%22values%22%3A%5B%22username-password%22%5D%7D%7D%7D&client_id=myClient&response_type=id_token&scope=openid%20profile&redirect_uri=https://www.example.com:443/callback&nonce=abc123&state=123abc&prompt=login

    The prompt setting forces the end user to authenticate explicitly regardless of any implied consent.

    When you request essential claims, AM authenticates the end user again. Learn more in Request processing.

    AM redirects to the application sign-in URL (redirect_uri) with the id_token in the fragment.

  3. Extract the ID token from the sign-in URL.

  4. Decode the ID token to display the acr claim:

    {
  "...": "...",
  "acr": "username-password"
}