Encrypt File to .p7m

Python example program to encrypt a file to produce a .p7m as output. A digital certificate (public-key) is used for encrypting.

Download Chilkat Python Library

import sys
import chilkat


crypt = chilkat.CkCrypt2()

#  Any string argument automatically begins the 30-day trial.
success = crypt.UnlockComponent("30-day trial")
if (success != True):
    print "Crypt component unlock failed"
    sys.exit()

#  Use public-key encryption with a digital certificate:
crypt.put_CryptAlgorithm("pki")

#  There are many ways to select and load a digital certificate.
#  Certs can be retrieved from the Windows registry-based
#  certificate stores, from database tables, files, etc.
#  This example will load a .cer file.
cert = chilkat.CkCert()

success = cert.LoadFromFile("myCert.cer")
if (success != True):
    print cert.lastErrorText()
    sys.exit()

crypt.SetEncryptCert(cert)

#  The CkEncryptFile can encrypt files of any size.  The
#  encryption occurs in streaming mode, so it is not necessary
#  to hold the entire contents of the file in memory at once.
success = crypt.CkEncryptFile("dude.gif","dude.p7m")
if (success != True):
    print crypt.lastErrorText()
    sys.exit()

#  To decrypt the file, you'll need the private key.
#  Also, the certificate should have already been installed
#  on the computer.  This is typically achieved by installing
#  from a .pfx file, or by importing from a certificate
#  authority's online web application.  If you are decrypting
#  from ASP, ASP.NET, or a Windows Service, you'll need to
#  import in a way that provides the calling process permission
#  to access and use the private key.  The procedure for
#  doing this is explained here:
#  http://blog.chilkatsoft.com/?p=149
# 
#  Also, there is no "SetDecryptCert" method.  The .p7m
#  contains information that allows the Chilkat component
#  to locate the certificate to be used for decryption.
#  The Chilkat Crypt component automatically searches
#  the Windows Current User certificate store and the
#  Local Machine certificate store.
success = crypt.CkDecryptFile("dude.p7m","dudeOut.gif")
if (success != True):
    print crypt.lastErrorText()
    sys.exit()