(Chilkat2-Python) Encrypt File using X.509 Certificate using AES in CBC Mode

Demonstrates how to encrypt a file using an X.509 Certificate's public key, where the underlying bulk encryption algorithm is 128-bit AES in CBC mode. (The underlying bulk encryption algorithm can be specified to be other algorithms/strengths.)

Chilkat2 Python Downloads install with pip pip3 install chilkat2 or download... Python Module for Windows, Linux, Alpine Linux, MacOS, Solaris

import sys
import chilkat2

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

crypt = chilkat2.Crypt2()

# Use public-key cryptography for encryption.
crypt.CryptAlgorithm = "pki"

# Get an X.509 certificate to use for encrypting.
# Note: Chilkat provides many different ways of loading a certificate, from many different formats,
# or if on Windows, from the installed certificates on the system.
# This example simply loads a certificate from a file.
# Also, for encryption, only the public key is needed.  Digital certificates embed the public key
# within the X.509 format itself.  Therefore, if you have a certificate, you also have the public key.
cert = chilkat2.Cert()
success = cert.LoadFromFile("qa_data/certs/testCert.cer")
if (success != True):
    print(cert.LastErrorText)
    sys.exit()

success = crypt.SetEncryptCert(cert)
if (success != True):
    print(crypt.LastErrorText)
    sys.exit()

# Indicate the underlying bulk encryption algorithm to be used:
crypt.Pkcs7CryptAlg = "aes"
crypt.KeyLength = 128

# Note: When doing public-key encryption the underlying bulk symmetric cipher mode will always be CBC. (at least with Chilkat...)

# There's one last option that could be set.  If is the RSA encryption encryption/padding scheme.
# By default, RSAES_PKCS1-V1_5 is used.  If desired, the OaepPadding property could be set to True to
# use RSAES_OAEP.  (We'll leave it set at the default value of False)
crypt.OaepPadding = False

# Everything is specified.  Now just encrypt...
# The output is PKCS7 in binary DER format.
success = crypt.CkEncryptFile("qa_data/hamlet.xml","qa_output/hamlet.p7")
if (success != True):
    print(crypt.LastErrorText)
    sys.exit()

print("Finished.")