JWT Token Generation

This section provides instructions on how to get the user claims of the authorized user as a JWT token with the validation response. 

Configurations

1. Open the <IS_HOME>/repository/conf/identity/identity.xml file and set the <Enabled> element (found under the <OAuth>,<AuthorizationContextTokenGeneration> elements) to true as shown in the code block below. 

   <AuthorizationContextTokenGeneration>
               <Enabled>true</Enabled>
               <TokenGeneratorImplClass>org.wso2.carbon.identity.oauth2.authcontext.JWTTokenGenerator</TokenGeneratorImplClass>
               <ClaimsRetrieverImplClass>org.wso2.carbon.identity.oauth2.authcontext.DefaultClaimsRetriever</ClaimsRetrieverImplClass>
               <ConsumerDialectURI>http://wso2.org/claims</ConsumerDialectURI>
               <SignatureAlgorithm>SHA256withRSA</SignatureAlgorithm>
               <AuthorizationContextTTL>15</AuthorizationContextTTL>
    </AuthorizationContextTokenGeneration> 

2. Add the following property under <OAUTH> section to use the JWT Token Builder instead of the default Token Builder.

   <IdentityOAuthTokenGenerator>org.wso2.carbon.identity.oauth2.token.JWTTokenIssuer</IdentityOAuthTokenGenerator> 

   If you need to use a self-contained access token generator, make sure you change the above values accordingly.

3. The following configurations are optional and can be configured as needed.

1. See the Extension Points for OAuth topic for more details about the usage of the 'TokenGeneratorImplClass' and 'ClaimsRetrieverImplClass'. 

2. ConsumerDialectURI: Defines the URI for the claim dialect under which the user attributes need to be retrieved. 

3. SignatureAlgorithm: Defines the algorithm to be used in signing the payload that carries user claims. If you want to disable signing of the JWT token, set this element to "NONE". 

   <SignatureAlgorithm>NONE</SignatureAlgorithm>

4. AuthorizationContextTTL: Defines the expiry time for JWT token in minutes.

Retrieving user claims with the JWT 

User claims can be retrieved using the ID token or the userinfo endpoint. For more information, see Basic Client Profile with Playground.

You can access the userinfo endpoint with the received access token using the following curl command. As per the specification, the received bearer token is sent using the HTTP Authorization header.

curl -k -H "Authorization: Bearer 4164157d677a6cd3a22e26e24c30135d" https://localhost:9443/oauth2/userinfo?schema=openid

As the response, WSO2 Identity Server returns a JSON with user claims.

{"sub":"PRIMARY\/alex","email":"alex@mymail.com","name":"Alex Anderson","family_name":"Anderson","preferred_username":"alexanders","given_name":"Alex"}

Signature verification

The signature verification can be done similar to the ID token signature verification. 

package org.sample;

import java.io.InputStream;
import java.security.KeyStore;
import java.security.cert.Certificate;
import java.security.interfaces.RSAPublicKey;

import com.nimbusds.jose.JWSVerifier;
import com.nimbusds.jose.crypto.RSASSAVerifier;
import com.nimbusds.jwt.SignedJWT;

public class ValidateRSASignature {

    public static void main(String[] args) throws Exception {
        RSAPublicKey publicKey = null;
        InputStream file = ClassLoader
                .getSystemResourceAsStream("wso2carbon.jks");
        KeyStore keystore = KeyStore.getInstance(KeyStore.getDefaultType());
        keystore.load(file, "wso2carbon".toCharArray());

        String alias = "wso2carbon";

        // Get certificate of public key
        Certificate cert = keystore.getCertificate(alias);
        // Get public key
        publicKey = (RSAPublicKey) cert.getPublicKey();

        // Enter JWT String here
        String signedJWTAsString = "eyJhbGciOiJSUzI1NiJ9.eyJzdWIiOiJhbGljZSIsImlzcyI6Imh0d";

        SignedJWT signedJWT = SignedJWT.parse(signedJWTAsString);

        JWSVerifier verifier = new RSASSAVerifier(publicKey);

        if (signedJWT.verify(verifier)) {
            System.out.println("Signature is Valid");
        } else {
            System.out.println("Signature is NOT Valid");
        }
    }
}