(Java) JWE using PBES2 Key Wrapping

Demonstrates how to create and decrypt a JWE that using PBES2 key wrapping.

This example demonstrates PBES2 with HMAC SHA-256 and A128KW wrapping. It is also possible to do the following by simply changing the "alg" parameter:

• PBES2 with HMAC SHA-384 and A192KW wrapping
• PBES2 with HMAC SHA-512 and A256KW wrapping

Note: This example requires Chilkat v9.5.0.66 or greater.

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import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    // This requires the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // Note: This example requires Chilkat v9.5.0.66 or greater.

    boolean success;
    String plaintext = "Live long and prosper.";

    CkJwe jwe = new CkJwe();

    // First build the JWE Protected Header..
    CkJsonObject jweProtHdr = new CkJsonObject();
    jweProtHdr.AppendString("alg","PBES2-HS256+A128KW");
    jweProtHdr.AppendString("enc","A128GCM");

    // PBES2 requires two additional parameters:
    // 1) A random salt parameter ("p2s") containing 8 or more bytes in base64url format.
    // 2) An iteration count parameter ("p2c").  A minimum count of 1000 is recommended.
    //    The iteration count is intended to make the PBES2 computation more expensive (time consuming)
    //    to prevent brute-force attacks.
    CkPrng prng = new CkPrng();
    jweProtHdr.AppendString("p2s",prng.genRandom(16,"base64url"));
    jweProtHdr.AppendString("p2c","1000");

    System.out.println("JWE Protected Header: " + jweProtHdr.emit());
    System.out.println("--");

    // Don't forget to actually provide the protected header to the JWE object:
    jwe.SetProtectedHeader(jweProtHdr);

    // Set the PBES2 password
    int recipientIndex = 0;
    jwe.SetPassword(recipientIndex,"top secret");

    // Encrypt and return the JWE:
    String strJwe = jwe.encrypt(plaintext,"utf-8");
    if (jwe.get_LastMethodSuccess() != true) {
        System.out.println(jwe.lastErrorText());
        return;
        }

    // Show the JWE we just created:
    System.out.println(strJwe);

    // Decrypt the JWE.
    CkJwe jwe2 = new CkJwe();
    success = jwe2.LoadJwe(strJwe);
    if (success != true) {
        System.out.println(jwe2.lastErrorText());
        return;
        }

    // Set the PBES2 password
    jwe2.SetPassword(recipientIndex,"top secret");

    // Decrypt.
    String originalPlaintext = jwe2.decrypt(0,"utf-8");
    if (jwe2.get_LastMethodSuccess() != true) {
        System.out.println(jwe2.lastErrorText());
        return;
        }

    System.out.println("original text: ");
    System.out.println(originalPlaintext);

    // Sample output:

    // JWE Protected Header: {"alg":"PBES2-HS256+A128KW","enc":"A128GCM","p2s":"z39rTEfRy1T1Yn_D1mZRlg","p2c":"1000"}
    // --
    // eyJhbGciOiJQQkVTMi1IUzI1NitBMTI4S1ciLCJlbmMiOiJBMTI4R0NNIiwicDJzIjoiejM5clRFZlJ5MVQxWW5fRDFtWlJsZyIsInAyYyI6IjEwMDAifQ.koYt6PrFmYwcwdcT7ZcvXHA1d-Xez5h4.luGlbvEnZp-7IsBOj42Yhw.YMTcfLf8Qe4zazozGV2OAu3cUdQ8Kg.rWub47ESWkc6IqZJTvSTmg
    // original text: 
    // Live long and prosper.
  }
}