(Android™) Ed25519 Sign and Verify

Demonstrates how to create an Ed25519 signature, and then to verify it.

Note: This example requires Chilkat v9.5.0.83 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.

    String privKeyHex = "1498b5467a63dffa2dc9d9e069caf075d16fc33fdd4c3b01bfadae6433767d93";
    String pubKeyHex = "b7a3c12dc0c8c748ab07525b701122b88bd78f600c76342d27f25e5f92444cde";

    CkPrivateKey privKey = new CkPrivateKey();
    // This example shows only one way of loading an Ed25519 private key.
    // Chilkat can load other formats (JWK, PEM, ASN.1 DER, etc.)  
    // You may do so by calling LoadAnyFormat or LoadAnyFormatFile.
    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.AppendString("Message for Ed25519 signing","utf-8");

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

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

    // The expected output is: 6dd355667fae4eb43c6e0ab92e870edb2de0a88cae12dbd8591507f584fe4912babff497f1b8edf9567d2483d54ddc6459bea7855281b7a246a609e3001a4e08

    // 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 Ed25519 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."
  }
}