(AutoIt) ECDSA Sign Data and Verify Signature

Demonstrates using the Elliptic Curve Digital Signature Algorithm to hash data and sign it. Also demonstrates how to verify the ECDSA signature.

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows

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

; To create an ECDSA signature, the data first needs to be hashed.  Then the hash
; is signed.

; Use Chilkat Crypt2 to generate a hash for any of the following
; hash algorithms: SHA256, SHA384, SHA512, SHA1, MD5, MD2, HAVAL, RIPEMD128/160/256/320

$oCrypt = ObjCreate("Chilkat.Crypt2")
$oCrypt.HashAlgorithm = "SHA256"
$oCrypt.Charset = "utf-8"
$oCrypt.EncodingMode = "base64"

; Hash a string.
Local $sHash1 = $oCrypt.HashStringENC("The quick brown fox jumps over the lazy dog")
ConsoleWrite("hash1 = " & $sHash1 & @CRLF)

; Or hash a file..
Local $sHash2 = $oCrypt.HashFileENC("qa_data/hamlet.xml")
ConsoleWrite("hash2 = " & $sHash2 & @CRLF)

; (The Crypt2 API provides many other ways to hash data..)

; -----------------------------------------------------------
; An ECDSA private key is used for signing.  The public key is for signature verification.
; Load our ECC private key.
; Our private key file contains this:

; 	// -----BEGIN PRIVATE KEY-----
; 	MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQg3J8q/24D1sEKGdP9
; 	72MGYElLGpw/a56Y3t6pfON3uhShRANCAATlSmoizyhAwoYZAOuFBATl07/1RR54
; 	a1Dzfm16grxJe666AGKR+bSs24hk7TEpaeCTvT8YOOM3l+xKFg7zq6Q9
; 	-----END PRIVATE KEY-----

$oPrivKey = ObjCreate("Chilkat.PrivateKey")
Local $bSuccess = $oPrivKey.LoadPemFile("qa_data/ecc/secp256r1-key-pkcs8.pem")
If ($bSuccess <> True) Then
    ConsoleWrite($oPrivKey.LastErrorText & @CRLF)
    Exit
EndIf

; We'll need a PRNG source for random number generation.
; Use Chilkat's PRNG (for the Fortuna PRNG algorithm).
$oPrng = ObjCreate("Chilkat.Prng")

; Sign the hash..
$oEcdsa = ObjCreate("Chilkat.Ecc")
Local $sEcdsaSigBase64 = $oEcdsa.SignHashENC($sHash1,"base64",$oPrivKey,$oPrng)
If ($oEcdsa.LastMethodSuccess <> True) Then
    ConsoleWrite($oEcdsa.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite("ECDSA signature = " & $sEcdsaSigBase64 & @CRLF)

; -----------------------------------------------------------
; Now let's verify the signature using the public key.

$oPubKey = ObjCreate("Chilkat.PublicKey")
$bSuccess = $oPubKey.LoadFromFile("qa_data/ecc/secp256r1-pubkey.pem")
If ($bSuccess <> True) Then
    ConsoleWrite($oPubKey.LastErrorText & @CRLF)
    Exit
EndIf

Local $iResult = $oEcdsa.VerifyHashENC($sHash1,$sEcdsaSigBase64,"base64",$oPubKey)
If ($iResult = 1) Then
    ConsoleWrite("Signature is valid." & @CRLF)
    Exit
EndIf

If ($iResult = 0) Then
    ConsoleWrite("Signature is invalid." & @CRLF)
    Exit
EndIf

If ($iResult < 0) Then
    ConsoleWrite($oEcdsa.LastErrorText & @CRLF)
    ConsoleWrite("The VerifyHashENC method call failed." & @CRLF)
    Exit
EndIf