Java

JWS Using HMAC SHA-256

See more JSON Web Signatures (JWS) Examples

Creates a JSON Web Signatures (JWS) using HMAC SHA-256. 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;

    //  This requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    //  First create the JWS Protected Header
    CkJsonObject jwsProtHdr = new CkJsonObject();
    jwsProtHdr.AppendString("typ","JWT");
    jwsProtHdr.AppendString("alg","HS256");
    System.out.println("JWS Protected Header: " + jwsProtHdr.emit());

    //  Output:
    //  JWS Protected Header: {"typ":"JWT","alg":"HS256"}

    CkJws jws = new CkJws();

    //  Set the HMAC key:
    String hmacKey = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow";
    int signatureIndex = 0;
    jws.SetMacKey(signatureIndex,hmacKey,"base64url");

    //  Set the protected header:
    jws.SetProtectedHeader(signatureIndex,jwsProtHdr);

    //  Set the payload.
    boolean bIncludeBom = false;
    String payloadStr = "In our village, folks say God crumbles up the old moon into stars.";
    jws.SetPayload(payloadStr,"utf-8",bIncludeBom);

    //  Create the JWS
    //  By default, the compact serialization is used.
    String jwsCompact = jws.createJws();
    if (jws.get_LastMethodSuccess() == false) {
        System.out.println(jws.lastErrorText());
        return;
        }

    System.out.println("JWS: " + jwsCompact);

    //  sample output:
    //  JWS: eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.bsYsi8HJ0N6OqGI1hKQ9QQRNPxxA5qMpcHLtOvXatk8

    //  Now load the JWS, validate, and recover the original text.
    CkJws jws2 = new CkJws();

    //  Load the JWS.
    success = jws2.LoadJws(jwsCompact);

    //  Set the MAC key used for validation.
    signatureIndex = 0;
    jws2.SetMacKey(signatureIndex,hmacKey,"base64url");

    //  Validate the 1st (and only) signature at index 0..
    int v = jws2.Validate(signatureIndex);
    if (v < 0) {
        //  Perhaps Chilkat was not unlocked or the trial expired..
        System.out.println("Method call failed for some other reason.");
        System.out.println(jws2.lastErrorText());
        return;
        }

    if (v == 0) {
        System.out.println("Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both.");
        return;
        }

    //  If we get here, the signature was validated..
    System.out.println("Signature validated.");

    //  Recover the original content:
    System.out.println(jws2.getPayload("utf-8"));

    //  Examine the protected header:

    CkJsonObject joseHeader = new CkJsonObject();
    success = jws2.GetProtectedH(signatureIndex,joseHeader);
    if (success == false) {
        System.out.println(jws2.lastErrorText());
        return;
        }

    joseHeader.put_EmitCompact(false);

    System.out.println("Protected (JOSE) header:");
    System.out.println(joseHeader.emit());

    //  Output:

    //  	Signature validated.
    //  	In our village, folks say God crumbles up the old moon into stars.
    //  	Protected (JOSE) header:
    //  	{ 
    //  	  "typ": "JWT",
    //  	  "alg": "HS256"
    //  	}
  }
}