AutoIt

Encrypt a File to a PKCS7 (CMS) Message

Shows how to encrypt a file into a PKCS7 encrypted message using the recipient's certificate. Public-key encryption requires no private key. However, the recipient's private key is necessary for decryption. 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")

;  Load the recipient's digital certificate. 
;  We don't need the private key for encryption.
;  Only the public key is needed (which is included in a certificate).
$oCert1 = ObjCreate("Chilkat.Cert")
$bSuccess = $oCert1.LoadFromFile("qa_data/user1/cert_user1.pem")
;  Assume success for the example, but make sure your application checks for success/failure...
$oCrypt.SetEncryptCert($oCert1)

;  Indicate that we want PKI encryption (i.e. public-key infrastructure)
;  to produce a CMS message (Cryptographic Message Syntax/PKCS7),
;  that is be created with RSAES-OAEP padding, SHA256, and AES-256 for the
;  bulk encryption.
$oCrypt.CryptAlgorithm = "pki"
$oCrypt.Pkcs7CryptAlg = "aes"
$oCrypt.KeyLength = 256
$oCrypt.OaepHash = "sha256"
$oCrypt.OaepPadding = True

;  Load the file to be encrypted...
$oFileData = ObjCreate("Chilkat.BinData")
$bSuccess = $oFileData.LoadFile("qa_data/jpg/penguins.jpg")
;  Your app should check for success/failure..

;  Encrypt the data.  The contents of the fileData object are replaced with the PKCS7 encrypted message.
$bSuccess = $oCrypt.EncryptBd($oFileData)
If ($bSuccess <> True) Then
    ConsoleWrite($oCrypt.LastErrorText & @CRLF)
    Exit
EndIf

;  Save the PKCS7 encrypted message to a file..
$bSuccess = $oFileData.WriteFile("qa_output/pkcs7_encrypted.p7")

ConsoleWrite("OK." & @CRLF)