AutoIt

AES Encrypt and Decrypt a File

_LANGUAGE_ demonstrates how to AES encrypt a file of any size, and then decrypt. AutoIt

Local $bSuccess = False

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

$oCrypt = ObjCreate("Chilkat.Crypt2")

$oCrypt.CryptAlgorithm = "aes"

; CipherMode may be "ecb" or "cbc"
$oCrypt.CipherMode = "cbc"

; KeyLength may be 128, 192, 256
$oCrypt.KeyLength = 256

; The padding scheme determines the contents of the bytes
; that are added to pad the result to a multiple of the
; encryption algorithm's block size.  AES has a block
; size of 16 bytes, so encrypted output is always
; a multiple of 16.
$oCrypt.PaddingScheme = 0

; An initialization vector is required if using CBC mode.
; ECB mode does not use an IV.
; The length of the IV is equal to the algorithm's block size.
; It is NOT equal to the length of the key.
Local $sIvHex = "000102030405060708090A0B0C0D0E0F"
$oCrypt.SetEncodedIV $sIvHex,"hex"

; The secret key must equal the size of the key.  For
; 256-bit encryption, the binary secret key is 32 bytes.
; For 128-bit encryption, the binary secret key is 16 bytes.
Local $sKeyHex = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"
$oCrypt.SetEncodedKey $sKeyHex,"hex"

; Encrypt a file, producing the .aes as output.
; The input file is unchanged, the output .aes contains the encrypted
; contents of the input file.

; Note: The .aes output file has no file format.  It is simply a stream
; of bytes that resembles random binary data.
Local $sInFile = "/Users/chilkat/testData/pdf/sample.pdf"
Local $sOutFile = "/Users/chilkat/testData/p7m/sample.pdf.aes"
$bSuccess = $oCrypt.CkEncryptFile($sInFile,$sOutFile)
If ($bSuccess <> True) Then
    ConsoleWrite($oCrypt.LastErrorText & @CRLF)
    Exit
EndIf

; For demonstration purposes, a different instance of the object will be used
; for decryption.
$oDecrypt = ObjCreate("Chilkat.Crypt2")

; All settings must match to be able to decrypt:
$oDecrypt.CryptAlgorithm = "aes"
$oDecrypt.CipherMode = "cbc"
$oDecrypt.KeyLength = 256
$oDecrypt.PaddingScheme = 0
$oDecrypt.SetEncodedIV $sIvHex,"hex"
$oDecrypt.SetEncodedKey $sKeyHex,"hex"

; Decrypt the .aes
$sInFile = "/Users/chilkat/testData/p7m/sample.pdf.aes"
$sOutFile = "/Users/chilkat/testData/pdf/recovered.pdf"
$bSuccess = $oDecrypt.CkDecryptFile($sInFile,$sOutFile)
If ($bSuccess = False) Then
    ConsoleWrite($oDecrypt.LastErrorText & @CRLF)
    Exit
EndIf

ConsoleWrite("Success!" & @CRLF)