(VBScript) 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 ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

Dim fso, outFile
Set fso = CreateObject("Scripting.FileSystemObject")
'Create a Unicode (utf-16) output text file.
Set outFile = fso.CreateTextFile("output.txt", True, True)

' 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

alicePrivKey = "77076d0a7318a57d3c16c17251b26645df4c2f87ebc0992ab177fba51db92c2a"
bobPubKey = "de9edb7d7b7dc1b4d35b61c2ece435373f8343c85b78674dadfc7e146f882b4f"

' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.PrivateKey")
set privKey = 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.
success = privKey.LoadEd25519(alicePrivKey,"")
If (success = 0) Then
    outFile.WriteLine(privKey.LastErrorText)
    WScript.Quit
End If

' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.PublicKey")
set pubKey = CreateObject("Chilkat.PublicKey")
success = pubKey.LoadEd25519(bobPubKey)
If (success = 0) Then
    outFile.WriteLine(pubKey.LastErrorText)
    WScript.Quit
End If

' Create the shared secret:
' For versions of Chilkat < 10.0.0, use CreateObject("Chilkat_9_5_0.EdDSA")
set eddsa = CreateObject("Chilkat.EdDSA")
sharedSecret = eddsa.SharedSecretENC(privKey,pubKey,"hexlower")
If (eddsa.LastMethodSuccess = 0) Then
    outFile.WriteLine(eddsa.LastErrorText)
    WScript.Quit
End If

outFile.WriteLine("Computed: " & sharedSecret)
outFile.WriteLine("Expected: 4a5d9d5ba4ce2de1728e3bf480350f25e07e21c947d19e3376f09b3c1e161742")

outFile.Close