B4X

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.

B4X

Dim success As Boolean = False

'  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

Dim alicePrivKey As String = "77076d0a7318a57d3c16c17251b26645df4c2f87ebc0992ab177fba51db92c2a"
Dim bobPubKey As String = "de9edb7d7b7dc1b4d35b61c2ece435373f8343c85b78674dadfc7e146f882b4f"

Dim privKey As ChilkatPrivateKey
privKey.Initialize("privKey")
'  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.
success = privKey.LoadEd25519(alicePrivKey, "")
If success = False Then
    Log(privKey.LastErrorText)
    Return
End If


Dim pubKey As ChilkatPublicKey
pubKey.Initialize
success = pubKey.LoadEd25519(bobPubKey)
If success = False Then
    Log(pubKey.LastErrorText)
    Return
End If


'  Create the shared secret:
Dim eddsa As ChilkatEdDSA
eddsa.Initialize
Dim sharedSecret As String = eddsa.SharedSecretENC(privKey, pubKey, "hexlower")
If eddsa.LastMethodSuccess = False Then
    Log(eddsa.LastErrorText)
    Return
End If


Log("Computed: " & sharedSecret)
Log("Expected: 4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742")