JWSExample.java

package example;

import com.nimbusds.jose.JOSEException;
import com.nimbusds.jose.JWSAlgorithm;
import com.nimbusds.jose.JWSHeader;
import com.nimbusds.jose.JWSObject;
import com.nimbusds.jose.JWSSigner;
import com.nimbusds.jose.JWSVerifier;
import com.nimbusds.jose.Payload;
import com.nimbusds.jose.crypto.MACSigner;
import com.nimbusds.jose.crypto.MACVerifier;

import java.text.ParseException;

/**
 * Example use of JWS objects.
 *
 * @author Vladimir Dzhuvinov
 * @version $version$ (2012-10-23)
 */
public class JWSExample {

  public static void main(final String[] args) {

    // Create payload
    String message = "Hello world!";

    Payload payload = new Payload(message);

    System.out.println("JWS payload message: " + message);

    // Create JWS header with HS256 algorithm
    JWSHeader header = new JWSHeader(JWSAlgorithm.HS256);
    header.setContentType("text/plain");

    System.out.println("JWS header: " + header.toJSONObject());

    // Create JWS object
    JWSObject jwsObject = new JWSObject(header, payload);

    // Create HMAC signer
    String sharedKey = "a0a2abd8-6162-41c3-83d6-1cf559b46afc";

    System.out.println("HMAC key: " + sharedKey);

    JWSSigner signer = new MACSigner(sharedKey.getBytes());

    try {
      jwsObject.sign(signer);
    }
    catch (JOSEException e) {

      System.err.println("Couldn't sign JWS object: " + e.getMessage());
      return;
    }

    // Serialise JWS object to compact format
    String s = jwsObject.serialize();

    System.out.println("Serialised JWS object: " + s);

    // Parse back and check signature

    try {
      jwsObject = JWSObject.parse(s);
    }
    catch (ParseException e) {

      System.err.println("Couldn't parse JWS object: " + e.getMessage());
      return;
    }

    System.out.println("JWS object successfully parsed");

    JWSVerifier verifier = new MACVerifier(sharedKey.getBytes());

    boolean verifiedSignature = false;

    try {
      verifiedSignature = jwsObject.verify(verifier);
    }
    catch (JOSEException e) {

      System.err.println("Couldn't verify signature: " + e.getMessage());
    }

    if (verifiedSignature) {
      System.out.println("Verified JWS signature!");
    }
    else {
      System.out.println("Bad JWS signature!");
      return;
    }

    System.out.println("Recovered payload message: " + jwsObject.getPayload());
  }
}