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Manually Duplicate SetSecretKeyViaPassword

Demonstrates how to duplicate the password string to binary secret key computation of SetSecretKeyViaPassword.

This is a cryptographically weak way of generating a secret key from a password. The SetSecretKeyViaPassword method is deprecated and should not be used.

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

$oCrypt = ObjCreate("Chilkat.Crypt2")

; The password string is transformed to a binary secret key by computing the 
; MD5 digest (of the utf-8 password) to obtain 16 bytes.  
; If the KeyLength is greater than 16 bytes, then the MD5 digest of the Base64 encoding 
; of the utf-8 password is added.  A max of 32 bytes of key material is generated, and 
; this is truncated to the actual KeyLength required.

$oCrypt.CryptAlgorithm = "aes"
$oCrypt.KeyLength = 256

Local $sPassword = "this is my password"
$oCrypt.SetSecretKeyViaPassword $sPassword

; Examine the resulting SecretKey in hex:
ConsoleWrite("Computed Secret Key = " & $oCrypt.GetEncodedKey("hex") & @CRLF)

; Now perform the same computation manually:
$oSb = ObjCreate("Chilkat.StringBuilder")

$oCrypt.HashAlgorithm = "md5"
$oCrypt.Charset = "utf-8"
$oCrypt.EncodingMode = "hex"
$oSb.Append($oCrypt.HashStringENC($sPassword))

Local $sPasswordBase64 = $oCrypt.EncodeString($sPassword,"utf-8","base64")
$oSb.Append($oCrypt.HashStringENC($sPasswordBase64))

ConsoleWrite("Manually Computed = " & $oSb.GetAsString() & @CRLF)

; The output is:
; Computed Secret Key = 210D53992DFF432EC1B1A9698AF9DA16C7E90518F90E24828F78EC9E0A413B36
; Manually Computed = 210D53992DFF432EC1B1A9698AF9DA16C7E90518F90E24828F78EC9E0A413B36