APEREO CASDocumentation

Enterprise Authentication for All Earthlings and Beyond

Identity, Single Sign-On and Access Management
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Discovery - OpenID Connect Authentication

OpenID connect discovery is the process of determining the location of the provider. Discovery returns a JSON listing of the OpenID/OAuth endpoints, supported scopes and claims, public keys used to sign the tokens, and other details. The clients can use this information to construct a request to the CAS OpenID connect server.

The following settings and properties are available from the CAS configuration catalog:

cas.authn.oidc.discovery.acr-values-supportedList of ACR values supported.
no default

List of ACR values supported. This discovery element contains a list of the supported acr values supported by this server. Support for authentication context class references is implemented in form of acr_values as part of the original authorization request, which is mostly taken into account by the multifactor authentication features of CAS. Once successful, acr and amr values are passed back to the relying party as part of the ID token.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.authorization-response-issuer-parameter-supportedParameter indicating whether the authorization server provides the iss parameter in the authorization response.
false

Parameter indicating whether the authorization server provides the iss parameter in the authorization response.

Type
Boolean
Default
false
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.backchannel-authentication-request-signing-alg-values-supportedList of the JWS signing algorithms (alg values) supported by the CAS for signed authentication requests.
no default

List of the JWS signing algorithms (alg values) supported by the CAS for signed authentication requests. If omitted, signed authentication requests are not supported by the CAS.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.backchannel-token-delivery-modes-supportedSupported backchannel token delivery modes used for CIBA.
no default

Supported backchannel token delivery modes used for CIBA.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.backchannel-user-code-parameter-supportedBoolean value specifying whether the OP supports the use of the user_code parameter.
false

Boolean value specifying whether the OP supports the use of the user_code parameter.

Type
Boolean
Default
false
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.claim-types-supportedSupported claim types.
no default

Supported claim types.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.claimsList of supported claims.
no default

List of supported claims.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.claims-in-verified-claims-supportedList of the supported verified claims.
no default

List of the supported verified claims.

Type
Set<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.claims-parameter-supportedSpecifying whether this provider supports use of the claims parameter.
true

Specifying whether this provider supports use of the claims parameter.

Type
Boolean
Default
true
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.code-challenge-methods-supportedList of PKCE code challenge methods supported.
no default

List of PKCE code challenge methods supported.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.documents-supportedNeeded when #evidenceSupported contains document or id_document .
no default

Needed when #evidenceSupported contains document or id_document. Set containing all identity document types utilized by the CAS for identity verification.

Type
Set<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.documents-validation-methods-supportedSet containing the validation methods the CAS supports.
no default

Set containing the validation methods the CAS supports.

Type
Set<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.documents-verification-methods-supportedSet containing the verification methods the CAS supports.
no default

Set containing the verification methods the CAS supports.

Type
Set<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.dpop-signing-alg-values-supportedA array containing a list of the JWS "alg" values supported by the CAS authorization server for DPoP proof JWTs.
no default

A array containing a list of the JWS "alg" values supported by the CAS authorization server for DPoP proof JWTs.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.electronic-records-supportedNeeded when evidence_supported contains electronicrecord .
no default

Needed when evidence_supported contains electronicrecord. Set containing all electronic record types the CAS supports.

Type
Set<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.evidence-supportedSet containing all types of identity evidence the OP uses.
no default

Set containing all types of identity evidence the OP uses. This array may have zero or more members.

Type
Set<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.grant-types-supportedSupported grant types.
no default

Supported grant types.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.id-token-encryption-alg-values-supportedSupported algorithms for ID token encryption.
no default

Supported algorithms for ID token encryption.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.id-token-encryption-encoding-values-supportedSupported encoding strategies for ID token encryption.
no default

Supported encoding strategies for ID token encryption.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.id-token-signing-alg-values-supportedSupported algorithms for ID token signing.
no default

Supported algorithms for ID token signing.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.introspection-encrypted-response-alg-values-supportedAccepted values containing a list of the JWE encryption algorithms ( alg values) supported by the introspection endpoint to encrypt the content encryption key for introspection response.
no default

Accepted values containing a list of the JWE encryption algorithms (alg values) supported by the introspection endpoint to encrypt the content encryption key for introspection response.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.introspection-encrypted-response-encoding-values-supportedAccepted values containing a list of the JWE encryption algorithms ( enc values) supported by the introspection endpoint to encrypt the introspection response.
no default

Accepted values containing a list of the JWE encryption algorithms (enc values) supported by the introspection endpoint to encrypt the introspection response.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.introspection-signed-response-alg-values-supportedAccepted values containing a list of the JWS signing algorithms supported by the introspection endpoint to sign the response.
no default

Accepted values containing a list of the JWS signing algorithms supported by the introspection endpoint to sign the response.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.introspection-supported-authentication-methodsSupported authentication methods for introspection.
no default

Supported authentication methods for introspection.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.native-sso-supportedValue indicating whether native SSO flows are supported.
true

Value indicating whether native SSO flows are supported.

Type
Boolean
Default
true
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.prompt-values-supportedSupported prompt values.
no default

Supported prompt values. If CAS receives a prompt value that it does not support (not declared in the prompt_values_supported metadata field) the CAS SHOULD respond with an HTTP 400 (Bad Request) status code and an error value of invalid request.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.request-object-encryption-alg-values-supportedSupported algorithms for request object encryption.
no default

Supported algorithms for request object encryption.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.request-object-encryption-encoding-values-supportedSupported encoding strategies for request object encryption.
no default

Supported encoding strategies for request object encryption.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.request-object-signing-alg-values-supportedSupported algorithms for request object signing.
no default

Supported algorithms for request object signing.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.request-parameter-supportedSpecifying whether this provider supports use of the request parameter.
true

Specifying whether this provider supports use of the request parameter.

Type
Boolean
Default
true
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.request-uri-parameter-supportedSpecifying whether this provider supports use of the request_uri parameter.
true

Specifying whether this provider supports use of the request_uri parameter.

Type
Boolean
Default
true
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.require-pushed-authorization-requestsBoolean parameter indicating whether the authorization server (CAS) accepts authorization request data only via the pushed authorization request method.
false

Boolean parameter indicating whether the authorization server (CAS) accepts authorization request data only via the pushed authorization request method.

Type
Boolean
Default
false
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.response-modes-supportedSupported response modes.
no default

Supported response modes.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.response-types-supportedSupported response types.
no default

Supported response types. The Response Mode request parameter response_mode informs the Authorization Server of the mechanism to be used for returning Authorization Response parameters from the Authorization Endpoint. Each Response Type value also defines a default Response Mode mechanism to be used, if no Response Mode is specified using the request parameter.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.scopesList of supported scopes.
no default

List of supported scopes.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.subject-typesList of supported subject types.
no default

List of supported subject types.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.tls-client-certificate-bound-access-tokensBoolean value indicating server support for mutual-TLS client certificate-bound access tokens.
false

Boolean value indicating server support for mutual-TLS client certificate-bound access tokens.

Type
Boolean
Default
false
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.token-endpoint-auth-methods-supportedList of client authentication methods supported by token endpoint.
no default

List of client authentication methods supported by token endpoint.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.token-endpoint-auth-signing-alg-values-supportedSigning algorithms supported by the token endpoint for the JWT that authenticates the client under the private_key_jwt and client_secret_jwt authentication methods.
no default

Signing algorithms supported by the token endpoint for the JWT that authenticates the client under the private_key_jwt and client_secret_jwt authentication methods. RFC 8414 requires this to be published whenever either method is advertised in #tokenEndpointAuthMethodsSupported, and forbids the value none.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.trust-frameworks-supportedSet containing all supported trust frameworks.
no default

Set containing all supported trust frameworks. This array must have at least one member.

Type
Set<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.user-info-encryption-alg-values-supportedSupported algorithms for user-info encryption.
no default

Supported algorithms for user-info encryption.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.user-info-encryption-encoding-values-supportedSupported encoding strategies for user-info encryption.
no default

Supported encoding strategies for user-info encryption.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.user-info-signing-alg-values-supportedSupported algorithms for user-info signing.
no default

Supported algorithms for user-info signing.

Type
List<String>
Default
none
Defined by
OidcDiscoveryProperties
cas.authn.oidc.discovery.verified-claims-supportedBoolean value indicating support for verified_claims, i.e., the OpenID Connect for Identity Assurance extension.
true

Boolean value indicating support for verified_claims, i.e., the OpenID Connect for Identity Assurance extension.

Type
Boolean
Default
true
Defined by
OidcDiscoveryProperties

Required settings may be needed to activate or affect the feature; review them even when they have a default. Optional settings only need to be set to change a default or to turn on the behavior they control. Third party settings belong to libraries such as Spring Boot that CAS builds on; their own documentation may have more detail.

Notes on configuration

Configuration Metadata

The collection of configuration properties listed in this section are automatically generated from the CAS source and components that contain the actual field definitions, types, descriptions, modules, etc. This metadata may not always be 100% accurate, or could be lacking details and sufficient explanations.

Be Selective

This section is meant as a guide only. Do NOT copy/paste the entire collection of settings into your CAS configuration; rather pick only the properties that you need. Do NOT enable settings unless you are certain of their purpose and do NOT copy settings into your configuration only to keep them as reference. All these ideas lead to upgrade headaches, maintenance nightmares and premature aging.

YAGNI

Note that for nearly ALL use cases, declaring and configuring properties listed here is sufficient. You should NOT have to explicitly massage a CAS XML/Java/etc configuration file to design an authentication handler, create attribute release policies, etc. CAS at runtime will auto-configure all required changes for you. If you are unsure about the meaning of a given CAS setting, do NOT turn it on without hesitation. Review the codebase or better yet, ask questions to clarify the intended behavior.

Naming Convention

Property names can be specified in very relaxed terms. For instance cas.someProperty, cas.some-property, cas.some_property are all valid names. While all forms are accepted by CAS, there are certain components (in CAS and other frameworks used) whose activation at runtime is conditional on a property value, where this property is required to have been specified in CAS configuration using kebab case. This is both true for properties that are owned by CAS as well as those that might be presented to the system via an external library or framework such as Spring Boot, etc.

:information_source: Note

When possible, properties should be stored in lower-case kebab format, such as cas.property-name=value. The only possible exception to this rule is when naming actuator endpoints; The name of the actuator endpoints (i.e. ssoSessions) MUST remain in camelCase mode.

Settings and properties that are controlled by the CAS platform directly always begin with the prefix cas. All other settings are controlled and provided to CAS via other underlying frameworks and may have their own schemas and syntax. BE CAREFUL with the distinction. Unrecognized properties are rejected by CAS and/or frameworks upon which CAS depends. This means if you somehow misspell a property definition or fail to adhere to the dot-notation syntax and such, your setting is entirely refused by CAS and likely the feature it controls will never be activated in the way you intend.

Validation

Configuration properties are automatically validated on CAS startup to report issues with configuration binding, especially if defined CAS settings cannot be recognized or validated by the configuration schema. Additional validation processes are also handled via Configuration Metadata and property migrations applied automatically on startup by Spring Boot and family.

Indexed Settings

CAS settings able to accept multiple values are typically documented with an index, such as cas.some.setting[0]=value. The index [0] is meant to be incremented by the adopter to allow for distinct multiple configuration blocks.