Chilkat2-Python

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. Chilkat2-Python

import sys
import chilkat2

success = False

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

crypt = chilkat2.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).
cert1 = chilkat2.Cert()
success = cert1.LoadFromFile("qa_data/user1/cert_user1.pem")
# Assume success for the example, but make sure your application checks for success/failure...
crypt.SetEncryptCert(cert1)

# 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.
crypt.CryptAlgorithm = "pki"
crypt.Pkcs7CryptAlg = "aes"
crypt.KeyLength = 256
crypt.OaepHash = "sha256"
crypt.OaepPadding = True

# Load the file to be encrypted...
fileData = chilkat2.BinData()
success = fileData.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.
success = crypt.EncryptBd(fileData)
if (success != True):
    print(crypt.LastErrorText)
    sys.exit()

# Save the PKCS7 encrypted message to a file..
success = fileData.WriteFile("qa_output/pkcs7_encrypted.p7")

print("OK.")