(Lianja) 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.

Chilkat Lianja Extension Download Chilkat Lianja Extension

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

loCrypt = createobject("CkCrypt2")

// 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).
loCert1 = createobject("CkCert")
llSuccess = loCert1.LoadFromFile("qa_data/user1/cert_user1.pem")
// Assume success for the example, but make sure your application checks for success/failure...
loCrypt.SetEncryptCert(loCert1)

// 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.
loCrypt.CryptAlgorithm = "pki"
loCrypt.Pkcs7CryptAlg = "aes"
loCrypt.KeyLength = 256
loCrypt.OaepHash = "sha256"
loCrypt.OaepPadding = .T.

// Load the file to be encrypted...
loFileData = createobject("CkBinData")
llSuccess = loFileData.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.
llSuccess = loCrypt.EncryptBd(loFileData)
if (llSuccess <> .T.) then
    ? loCrypt.LastErrorText
    release loCrypt
    release loCert1
    release loFileData
    return
endif

// Save the PKCS7 encrypted message to a file..
llSuccess = loFileData.WriteFile("qa_output/pkcs7_encrypted.p7")

? "OK."


release loCrypt
release loCert1
release loFileData