Xbase++

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. Xbase++

LOCAL nSuccess
LOCAL oCrypt
LOCAL oCert1
LOCAL oFileData

nSuccess := 0

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

oCrypt := CreateObject("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 := CreateObject("Chilkat.Cert")
nSuccess := 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 := 1

//  Load the file to be encrypted...
oFileData := CreateObject("Chilkat.BinData")
nSuccess := 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.
nSuccess := oCrypt:EncryptBd(oFileData)
IF (nSuccess != 1)
    ? oCrypt:LastErrorText
    oCrypt:destroy()
    oCert1:destroy()
    oFileData:destroy()
    RETURN
ENDIF

//  Save the PKCS7 encrypted message to a file..
nSuccess := oFileData:WriteFile("qa_output/pkcs7_encrypted.p7")

? "OK."

oCrypt:destroy()
oCert1:destroy()
oFileData:destroy()