How to create a JSON Web Signature (JWS) with RSA

Question

I was looking to develop / create a JWT with RSA using Nimbus Jose+Jwt library. I wanted to use the below version

<nimbus-jwt-version>3.1.2</nimbus-jwt-version>
<dependency>
    <groupId>com.nimbusds</groupId>
    <artifactId>nimbus-jose-jwt</artifactId>
    <version>${nimbus-jwt-version}</version>
</dependency>

This will create a Token value and also once the token is created it will extracts the claims out of it. Please help with the code.

Answer 1

Here you go. Today is 13th-Aug-16 and certainly this is not the latest dependency, today latest dependency is 4.23. We should need to refactor the code to make it working. Will be posting the logic soon.

import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;
import java.util.UUID;

import com.nimbusds.jose.EncryptionMethod;
import com.nimbusds.jose.JOSEException;
import com.nimbusds.jose.JWEAlgorithm;
import com.nimbusds.jose.JWEHeader;
import com.nimbusds.jose.crypto.RSADecrypter;
import com.nimbusds.jose.crypto.RSAEncrypter;
import com.nimbusds.jwt.EncryptedJWT;
import com.nimbusds.jwt.JWTClaimsSet;

public class JWTNimbusDemo {
    public static void main(String[] args) {
        KeyPairGenerator keyPairGenerator;
        try {
            keyPairGenerator = KeyPairGenerator.getInstance("RSA");

            keyPairGenerator.initialize(1024);

            // generate the key pair
            KeyPair keyPair = keyPairGenerator.genKeyPair();

            // create KeyFactory and RSA Keys Specs
            KeyFactory keyFactory = KeyFactory.getInstance("RSA");
            RSAPublicKeySpec publicKeySpec = keyFactory.getKeySpec(keyPair.getPublic(), RSAPublicKeySpec.class);
            RSAPrivateKeySpec privateKeySpec = keyFactory.getKeySpec(keyPair.getPrivate(), RSAPrivateKeySpec.class);

            // generate (and retrieve) RSA Keys from the KeyFactory using Keys Specs
            RSAPublicKey publicRsaKey = (RSAPublicKey) keyFactory.generatePublic(publicKeySpec);
            RSAPrivateKey privateRsaKey  = (RSAPrivateKey) keyFactory.generatePrivate(privateKeySpec);

            JWTClaimsSet claimsSet = new JWTClaimsSet();
            claimsSet.setIssuer("https://my-auth-server.com");
            claimsSet.setSubject("John Kerr");
            claimsSet.setAudience(getAudience());
            claimsSet.setExpirationTime(new Date(new Date().getTime() + 1000*60*10));
            claimsSet.setNotBeforeTime(new Date());
            claimsSet.setJWTID(UUID.randomUUID().toString());

            System.out.println("--------------------------");
            System.out.println("Claim Set : \n"+claimsSet.toJSONObject());

            // create the JWT header and specify:
            //  RSA-OAEP as the encryption algorithm
            //  128-bit AES/GCM as the encryption method
            JWEHeader header = new JWEHeader(JWEAlgorithm.RSA_OAEP, EncryptionMethod.A128GCM);

            // create the EncryptedJWT object
            EncryptedJWT jwt = new EncryptedJWT(header, claimsSet);

            // create an RSA encrypter with the specified public RSA key
            RSAEncrypter encrypter = new RSAEncrypter(publicRsaKey);

            // do the actual encryption
            jwt.encrypt(encrypter);

            // serialize to JWT compact form
            String jwtString = jwt.serialize();
            System.out.println("\nJwt Compact Form : "+jwtString);

            // in order to read back the data from the token using your private RSA key:
            // parse the JWT text string using EncryptedJWT object
            jwt = EncryptedJWT.parse(jwtString);

            // create a decrypter with the specified private RSA key
            RSADecrypter decrypter = new RSADecrypter(privateRsaKey);

            // do the decryption
            jwt.decrypt(decrypter);

            // print out the claims

            System.out.println("===========================================================");
            System.out.println("Issuer: [ " + jwt.getJWTClaimsSet().getIssuer() + "]");
            System.out.println("Subject: [" + jwt.getJWTClaimsSet().getSubject()+ "]");
            System.out.println("Audience size: [" + jwt.getJWTClaimsSet().getAudience().size()+ "]");
            System.out.println("Expiration Time: [" + jwt.getJWTClaimsSet().getExpirationTime()+ "]");
            System.out.println("Not Before Time: [" + jwt.getJWTClaimsSet().getNotBeforeTime()+ "]");
            System.out.println("Issue At: [" + jwt.getJWTClaimsSet().getIssueTime()+ "]");
            System.out.println("JWT ID: [" + jwt.getJWTClaimsSet().getJWTID()+ "]");
            System.out.println("===========================================================");

        } catch (NoSuchAlgorithmException | InvalidKeySpecException | JOSEException | ParseException e) {
            System.out.println(e.getMessage());
        }
    }

    private static List<String> getAudience(){
        List<String> audience = new ArrayList<>();
        audience.add("https://my-web-app.com");
        audience.add("https://your-web-app.com");
        return audience;
    }
}