(Android™) Ed25519ph Sign and Verify

Demonstrates how to create an Ed25519ph signature, and then to verify it.

Note: This example requires Chilkat v9.5.0.91 or greater.

Chilkat Android™ Downloads Android™ Java Libraries Android C/C++ Libraries

// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

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

    // Use the following test vector from https://www.rfc-editor.org/rfc/rfc8032#page-30

    //    -----TEST abc
    // 
    //    ALGORITHM:
    //    Ed25519ph
    // 
    //    SECRET KEY:
    //    833fe62409237b9d62ec77587520911e
    //    9a759cec1d19755b7da901b96dca3d42
    // 
    //    PUBLIC KEY:
    //    ec172b93ad5e563bf4932c70e1245034
    //    c35467ef2efd4d64ebf819683467e2bf
    // 
    //    MESSAGE (length 3 bytes):
    //    616263
    // 
    //    SIGNATURE:
    //    98a70222f0b8121aa9d30f813d683f80
    //    9e462b469c7ff87639499bb94e6dae41
    //    31f85042463c2a355a2003d062adf5aa
    //    a10b8c61e636062aaad11c2a26083406

    String privKeyHex = "833fe62409237b9d62ec77587520911e9a759cec1d19755b7da901b96dca3d42";
    String pubKeyHex = "ec172b93ad5e563bf4932c70e1245034c35467ef2efd4d64ebf819683467e2bf";

    CkPrivateKey privKey = new CkPrivateKey();
    boolean success = privKey.LoadEd25519(privKeyHex,pubKeyHex);
    if (success == false) {
        Log.i(TAG, privKey.lastErrorText());
        return;
        }

    // The data to be signed...
    CkBinData bd = new CkBinData();
    bd.AppendEncoded("616263","hex");

    CkEdDSA eddsa = new CkEdDSA();
    // Indicate we want the Ed25519ph instance.
    eddsa.put_Algorithm("Ed25519ph");

    String hexSig = eddsa.signBdENC(bd,"hexlower",privKey);

    Log.i(TAG, "signature = " + hexSig);

    // The expected output is: 98a70222f0b8121aa9d30f813d683f80....

    // Verify the signature..
    CkPublicKey pubKey = new CkPublicKey();
    success = pubKey.LoadEd25519(pubKeyHex);
    if (success == false) {
        Log.i(TAG, pubKey.lastErrorText());
        return;
        }

    boolean bVerified = eddsa.VerifyBdENC(bd,hexSig,"hexlower",pubKey);
    if (bVerified == false) {
        Log.i(TAG, eddsa.lastErrorText());
        Log.i(TAG, "Failed to verify the signature.");
        return;
        }

    Log.i(TAG, "The Ed25519ph signature is verified!");

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}