[role="xpack"] [[security-api-oidc-prepare-authentication]] === OpenID Connect Prepare Authentication API Creates an oAuth 2.0 authentication request as a URL string based on the configuration of the respective OpenID Connect authentication realm in {es}. [[security-api-oidc-prepare-authentication-request]] ==== {api-request-title} `POST /_security/oidc/prepare` //[[security-api-oidc-prepare-authentication-prereqs]] //==== {api-prereq-title} [[security-api-oidc-prepare-authentication-desc]] ==== {api-description-title} The response of this API is a URL pointing to the Authorization Endpoint of the configured OpenID Connect Provider and can be used to redirect the browser of the user in order to continue the authentication process. {es} exposes all the necessary OpenID Connect related functionality via the OpenID Connect APIs. These APIs are used internally by {kib} in order to provide OpenID Connect based authentication, but can also be used by other, custom web applications or other clients. See also <> and <>. [[security-api-oidc-prepare-authentication-request-body]] ==== {api-request-body-title} The following parameters can be specified in the body of the request: `realm`:: The name of the OpenID Connect realm in {es} the configuration of which should be used in order to generate the authentication request. Cannot be specified when `iss` is specified. `state`:: String value used to maintain state between the authentication request and the response, typically used as a Cross-Site Request Forgery mitigation. If the caller of the API doesn't provide a value, {es} will generate one with sufficient entropy itself and return it in the response. `nonce`:: String value used to associate a Client session with an ID Token and to mitigate replay attacks. If the caller of the API doesn't provide a value, {es} will generate one with sufficient entropy itself and return it in the response. `issuer`:: In the case of a 3rd Party initiated Single Sign On, this is the Issuer Identifier for the OP that the RP is to send the Authentication Request to. Cannot be specified when `realm` is specified. `login_hint`:: In the case of a 3rd Party initiated Single Sign On, a string value to be included in the authentication request, as the `login_hint` parameter. This parameter is not valid when `realm` is specified [[security-api-oidc-prepare-authentication-example]] ==== {api-examples-title} The following example generates an authentication request for the OpenID Connect Realm `oidc1`: [source,js] -------------------------------------------------- POST /_security/oidc/prepare { "realm" : "oidc1" } -------------------------------------------------- // CONSOLE The following example output of the response contains the URI pointing to the Authorization Endpoint of the OpenID Connect Provider with all the parameters of the Authentication Request, as HTTP GET parameters: [source,js] -------------------------------------------------- { "redirect" : "http://127.0.0.1:8080/c2id-login?scope=openid&response_type=id_token&redirect_uri=https%3A%2F%2Fmy.fantastic.rp%2Fcb&state=4dbrihtIAt3wBTwo6DxK-vdk-sSyDBV8Yf0AjdkdT5I&nonce=WaBPH0KqPVdG5HHdSxPRjfoZbXMCicm5v1OiAj0DUFM&client_id=elasticsearch-rp", "state" : "4dbrihtIAt3wBTwo6DxK-vdk-sSyDBV8Yf0AjdkdT5I", "nonce" : "WaBPH0KqPVdG5HHdSxPRjfoZbXMCicm5v1OiAj0DUFM" } -------------------------------------------------- // TESTRESPONSE[s/4dbrihtIAt3wBTwo6DxK-vdk-sSyDBV8Yf0AjdkdT5I/\$\{body.state\}/] // TESTRESPONSE[s/WaBPH0KqPVdG5HHdSxPRjfoZbXMCicm5v1OiAj0DUFM/\$\{body.nonce\}/] The following example generates an authentication request for the OpenID Connect Realm `oidc1`, where the values for the state and the nonce have been generated by the client: [source,js] -------------------------------------------------- POST /_security/oidc/prepare { "realm" : "oidc1", "state" : "lGYK0EcSLjqH6pkT5EVZjC6eIW5YCGgywj2sxROO", "nonce" : "zOBXLJGUooRrbLbQk5YCcyC8AXw3iloynvluYhZ5" } -------------------------------------------------- // CONSOLE The following example output of the response contains the URI pointing to the Authorization Endpoint of the OpenID Connect Provider with all the parameters of the Authentication Request, as HTTP GET parameters: [source,js] -------------------------------------------------- { "redirect" : "http://127.0.0.1:8080/c2id-login?scope=openid&response_type=id_token&redirect_uri=https%3A%2F%2Fmy.fantastic.rp%2Fcb&state=lGYK0EcSLjqH6pkT5EVZjC6eIW5YCGgywj2sxROO&nonce=zOBXLJGUooRrbLbQk5YCcyC8AXw3iloynvluYhZ5&client_id=elasticsearch-rp", "state" : "lGYK0EcSLjqH6pkT5EVZjC6eIW5YCGgywj2sxROO", "nonce" : "zOBXLJGUooRrbLbQk5YCcyC8AXw3iloynvluYhZ5" } -------------------------------------------------- // TESTRESPONSE The following example generates an authentication request for a 3rd party initiated single sign on, specifying the issuer that should be used for matching the appropriate OpenID Connect Authentication realm: [source,js] -------------------------------------------------- POST /_security/oidc/prepare { "iss" : "http://127.0.0.1:8080", "login_hint": "this_is_an_opaque_string" } -------------------------------------------------- // CONSOLE The following example output of the response contains the URI pointing to the Authorization Endpoint of the OpenID Connect Provider with all the parameters of the Authentication Request, as HTTP GET parameters: [source,js] -------------------------------------------------- { "redirect" : "http://127.0.0.1:8080/c2id-login?login_hint=this_is_an_opaque_string&scope=openid&response_type=id_token&redirect_uri=https%3A%2F%2Fmy.fantastic.rp%2Fcb&state=4dbrihtIAt3wBTwo6DxK-vdk-sSyDBV8Yf0AjdkdT5I&nonce=WaBPH0KqPVdG5HHdSxPRjfoZbXMCicm5v1OiAj0DUFM&client_id=elasticsearch-rp", "state" : "4dbrihtIAt3wBTwo6DxK-vdk-sSyDBV8Yf0AjdkdT5I", "nonce" : "WaBPH0KqPVdG5HHdSxPRjfoZbXMCicm5v1OiAj0DUFM" } -------------------------------------------------- // TESTRESPONSE[s/4dbrihtIAt3wBTwo6DxK-vdk-sSyDBV8Yf0AjdkdT5I/\$\{body.state\}/] // TESTRESPONSE[s/WaBPH0KqPVdG5HHdSxPRjfoZbXMCicm5v1OiAj0DUFM/\$\{body.nonce\}/]