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Java

Sign a JWS with an HMAC Key

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.SetMacKey, which sets the symmetric MAC key for a signature. The key bytes are supplied in a named encoding such as hex or base64.

Background. HMAC-based JWS (for example HS256) authenticates the payload with a shared symmetric key that both signer and verifier possess.

Chilkat Java Downloads

Java
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[])
  {
    boolean success = false;

    CkJws jws = new CkJws();

    //  Protected header specifying HMAC-SHA256.
    CkJsonObject header = new CkJsonObject();
    header.UpdateString("alg","HS256");
    success = jws.SetProtectedHeader(0,header);
    if (success == false) {
        System.out.println(jws.lastErrorText());
        return;
        }

    boolean bIncludeBom = false;
    success = jws.SetPayload("This is the content to sign.","utf-8",bIncludeBom);
    if (success == false) {
        System.out.println(jws.lastErrorText());
        return;
        }

    //  Set the symmetric MAC key for signature 0.  The key bytes are provided in the named encoding (here
    //  base64).  In production, obtain the key from a secure source rather than hard-coding it.
    String base64Key = "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU=";
    success = jws.SetMacKey(0,base64Key,"base64");
    if (success == false) {
        System.out.println(jws.lastErrorText());
        return;
        }

    String jwsCompact = jws.createJws();
    if (jws.get_LastMethodSuccess() == false) {
        System.out.println(jws.lastErrorText());
        return;
        }

    System.out.println(jwsCompact);
  }
}