(C# UWP/WinRT) Ed25519 Key Exchange (Shared Secret)

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

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

Chilkat Universal Windows Platform (UWP) / WinRT Downloads Chilkat for the Universal Windows Platform (UWP)

// 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";

Chilkat.PrivateKey privKey = new Chilkat.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.
bool success = privKey.LoadEd25519(alicePrivKey,"");
if (success == false) {
    Debug.WriteLine(privKey.LastErrorText);
    return;
}

Chilkat.PublicKey pubKey = new Chilkat.PublicKey();
success = pubKey.LoadEd25519(bobPubKey);
if (success == false) {
    Debug.WriteLine(pubKey.LastErrorText);
    return;
}

// Create the shared secret:
Chilkat.EdDSA eddsa = new Chilkat.EdDSA();
string sharedSecret = eddsa.SharedSecretENC(privKey,pubKey,"hexlower");
if (eddsa.LastMethodSuccess == false) {
    Debug.WriteLine(eddsa.LastErrorText);
    return;
}

Debug.WriteLine("Computed: " + sharedSecret);
Debug.WriteLine("Expected: 4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742");