(Excel) Ed25519 Sign and Verify

Demonstrates how to create an Ed25519 signature, and then to verify it.

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

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' This example assumes the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.


privKeyHex = "1498b5467a63dffa2dc9d9e069caf075d16fc33fdd4c3b01bfadae6433767d93"

pubKeyHex = "b7a3c12dc0c8c748ab07525b701122b88bd78f600c76342d27f25e5f92444cde"

Dim privKey As Chilkat.PrivateKey
Set privKey = Chilkat.NewPrivateKey
' 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(privKeyHex,pubKeyHex)
If (success = False) Then
    Debug.Print privKey.LastErrorText
    Exit Sub
End If

' The data to be signed...
Dim bd As Chilkat.BinData
Set bd = Chilkat.NewBinData
Dim success As Boolean
success = bd.AppendString("Message for Ed25519 signing","utf-8")

Dim eddsa As Chilkat.EdDSA
Set eddsa = Chilkat.NewEdDSA

hexSig = eddsa.SignBdENC(bd,"hexlower",privKey)

Debug.Print "signature = "; hexSig

' The expected output is: 6dd355667fae4eb43c6e0ab92e870edb2de0a88cae12dbd8591507f584fe4912babff497f1b8edf9567d2483d54ddc6459bea7855281b7a246a609e3001a4e08

' Verify the signature..
Dim pubKey As Chilkat.PublicKey
Set pubKey = Chilkat.NewPublicKey
success = pubKey.LoadEd25519(pubKeyHex)
If (success = False) Then
    Debug.Print pubKey.LastErrorText
    Exit Sub
End If


bVerified = eddsa.VerifyBdENC(bd,hexSig,"hexlower",pubKey)
If (bVerified = False) Then
    Debug.Print eddsa.LastErrorText
    Debug.Print "Failed to verify the signature."
    Exit Sub
End If

Debug.Print "The Ed25519 signature is verified!"