Java

Ed25519 Key Exchange (Shared Secret)

See more Ed25519 Examples

Demonstrates how to create an Ed25519 shared secret for use in key exchange.

Note: This example requires Chilkat v9.5.0.83 or greater.

Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.EdDSA;
import com.chilkatsoft.chilkat2.PrivateKey;
import com.chilkatsoft.chilkat2.PublicKey;

public class ChilkatExample {

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

        // Alice's private key, a:
        //     77076d0a7318a57d3c16c17251b26645df4c2f87ebc0992ab177fba51db92c2a
        // Alice's public key, X25519(a, 9):
        //     8520f0098930a754748b7ddcb43ef75a0dbf3a0d26381af4eba4a98eaa9b4e6a
        // Bob's private key, b:
        //     5dab087e624a8a4b79e17f8b83800ee66f3bb1292618b6fd1c2f8b27ff88e0eb
        // Bob's public key, X25519(b, 9):
        //     de9edb7d7b7dc1b4d35b61c2ece435373f8343c85b78674dadfc7e146f882b4f
        // Their shared secret, K:
        //     4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742

        String alicePrivKey = "77076d0a7318a57d3c16c17251b26645df4c2f87ebc0992ab177fba51db92c2a";
        String bobPubKey = "de9edb7d7b7dc1b4d35b61c2ece435373f8343c85b78674dadfc7e146f882b4f";

        PrivateKey privKey = new PrivateKey();
        // 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.
        try {
            privKey.loadEd25519(alicePrivKey, "");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        PublicKey pubKey = new PublicKey();
        try {
            pubKey.loadEd25519(bobPubKey);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Create the shared secret:
        EdDSA eddsa = new EdDSA();
        String sharedSecret;
        try {
            sharedSecret = eddsa.sharedSecretENC(privKey, pubKey, "hexlower");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        System.out.println("Computed: " + sharedSecret);
        System.out.println("Expected: 4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742");
    }
}