(CkPython) Encrypt File to PKCS7 .p7m

CkPython example to public-key encrypt a file creating a PKCS#7 .p7m file as output. Also demonstrates how to decrypt the .p7m to recover the original file.

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import sys
import chilkat

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

crypt = chilkat.CkCrypt2()

# Indicate the public-key encryption is to be used.
# Do this by setting the encryption algorithm equal 
# to "PKI" (an acroynm for public-key infrastructure).
crypt.put_CryptAlgorithm("PKI")

# Indicate the inner symmetric encryption algorithm to be used.
# possible values are "aes", "des", "3des", and "rc2".
# For this example, we'll use 256-bit AES encryption.
crypt.put_Pkcs7CryptAlg("aes")
crypt.put_KeyLength(256)

# To encrypt, only a certificate w/ public key is needed.
# (The certificate w/ private key is required for decryption.)

# The LoadFromFile method can load virtually any certificate format:
# 1. DER encoded binary X.509 (.CER)
# 2. Base-64 encoded X.509 (.CER)
# 3. Cryptographic Message Syntax Standard - PKCS #7 Certificates (.P7B)
# 4. PEM format
encryptCert = chilkat.CkCert()
success = encryptCert.LoadFromFile("/Users/chilkat/testData/cer/acme.cer")
if (success != True):
    print(encryptCert.lastErrorText())
    sys.exit()

# Tell the crypt object to use the certificate for encrypting:
crypt.AddEncryptCert(encryptCert)

# Encrypt a file, producing a .p7m as output.
# The input file is unchanged, the output .p7m contains the encrypted
# contents of the input file.
inFile = "/Users/chilkat/testData/pdf/sample.pdf"
outFile = "/Users/chilkat/testData/p7m/sample.pdf.p7m"
success = crypt.CkEncryptFile(inFile,outFile)
if (success != True):
    print(crypt.lastErrorText())
    sys.exit()

# For demonstration purposes, a different instance of the object will be used
# for decryption.
decrypt = chilkat.CkCrypt2()

# To decrypt, the certificate w/ private key is required.  A PFX (also known
# as PKCS#12) is a common secure container for certs and private keys.
pfxFilename = "/Users/chilkat/testData/pfx/acme.pfx"
pfxPassword = "secret"

# Tell the component to look in the PFX file for certs and private keys.
success = decrypt.AddPfxSourceFile(pfxFilename,pfxPassword)
if (success != True):
    print(decrypt.lastErrorText())
    sys.exit()

# Tell the decrypt object that PKI (public key encryption) is to be used
# for decryptiong.
decrypt.put_CryptAlgorithm("PKI")
# There is no need to set the Pkcs7Alg or KeyLength because this information
# is contained within the .p7m

# Decrypt the .p7m
inFile = "/Users/chilkat/testData/p7m/sample.pdf.p7m"
outFile = "/Users/chilkat/testData/pdf/recovered.pdf"
success = decrypt.CkDecryptFile(inFile,outFile)
if (success == False):
    print(decrypt.lastErrorText())
    sys.exit()

print("Success!")