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Encrypt a file to a PKCS7 encrypted message using multiple certificates from different users

See more Encryption Examples

Demonstrates how to encrypt a file to a PKCS7 encrypted message using multiple certificates from different users. Any one of the users can decrypt using his/her own certificate + private key.

Note: When doing public key encryption, it is the public key that is used to encrypt. The private key is required for decryption.

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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")

;  Tell the crypt object to use 3 certificates.
;  Do this by calling AddEncryptCert for each certificate.

;  Load a 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.AddEncryptCert $oCert1

$oCert2 = ObjCreate("Chilkat.Cert")
$bSuccess = $oCert2.LoadFromFile("qa_data/user2/cert_user2.pem")
$oCrypt.AddEncryptCert $oCert2

$oCert3 = ObjCreate("Chilkat.Cert")
$bSuccess = $oCert3.LoadFromFile("qa_data/user3/cert_user3.pem")
$oCrypt.AddEncryptCert $oCert3

;  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-128 for the
;  bulk encryption.
$oCrypt.CryptAlgorithm = "pki"
$oCrypt.Pkcs7CryptAlg = "aes"
$oCrypt.KeyLength = 128
$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")

;  Now indicate that the PKCS7 output is to be returned in the base64 encoding.
$oCrypt.EncodingMode = "base64"

ConsoleWrite("OK." & @CRLF)