(Visual FoxPro) 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.

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LOCAL lcAlicePrivKey
LOCAL lcBobPubKey
LOCAL loPrivKey
LOCAL lnSuccess
LOCAL loPubKey
LOCAL loEddsa
LOCAL lcSharedSecret

* 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

lcAlicePrivKey = "77076d0a7318a57d3c16c17251b26645df4c2f87ebc0992ab177fba51db92c2a"
lcBobPubKey = "de9edb7d7b7dc1b4d35b61c2ece435373f8343c85b78674dadfc7e146f882b4f"

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.PrivateKey')
loPrivKey = CreateObject('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.
lnSuccess = loPrivKey.LoadEd25519(lcAlicePrivKey,"")
IF (lnSuccess = 0) THEN
    ? loPrivKey.LastErrorText
    RELEASE loPrivKey
    CANCEL
ENDIF

* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.PublicKey')
loPubKey = CreateObject('Chilkat.PublicKey')
lnSuccess = loPubKey.LoadEd25519(lcBobPubKey)
IF (lnSuccess = 0) THEN
    ? loPubKey.LastErrorText
    RELEASE loPrivKey
    RELEASE loPubKey
    CANCEL
ENDIF

* Create the shared secret:
* For versions of Chilkat < 10.0.0, use CreateObject('Chilkat_9_5_0.EdDSA')
loEddsa = CreateObject('Chilkat.EdDSA')
lcSharedSecret = loEddsa.SharedSecretENC(loPrivKey,loPubKey,"hexlower")
IF (loEddsa.LastMethodSuccess = 0) THEN
    ? loEddsa.LastErrorText
    RELEASE loPrivKey
    RELEASE loPubKey
    RELEASE loEddsa
    CANCEL
ENDIF

? "Computed: " + lcSharedSecret
? "Expected: 4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742"

RELEASE loPrivKey
RELEASE loPubKey
RELEASE loEddsa