Python Requires Chilkat v11.7.0+

Encrypt a PDF for a Certificate Instead of a Password

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Demonstrates certificate security, where a PDF is encrypted for one or more recipients and each opens it with their own certificate and private key. No password is involved. Only the public certificate of a recipient is needed to encrypt. Each recipient has its own permissions, and the changeSecurity permission gives a recipient owner rights. PreLoadCheck tells an application that a file is certificate-encrypted and which certificates can open it. A PDF that cannot be opened, because no matching certificate and private key were provided, fails to load. 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.

# The PDF used in this example is available at two_page_memo.pdf

# The recipient's certificate.  Only the public certificate is needed to encrypt.
recipient = chilkat2.Cert()
success = recipient.LoadFromFile("qa_data/certs/recipient.cer")
if (success == False):
    print(recipient.LastErrorText)
    sys.exit()

pdf = chilkat2.Pdf()
success = pdf.LoadFile("qa_data/pdf/two_page_memo.pdf")
if (success == False):
    print(pdf.LastErrorText)
    sys.exit()

# Call AddEncryptCert once for each recipient.
success = pdf.AddEncryptCert(recipient)
if (success == False):
    print(pdf.LastErrorText)
    sys.exit()

# recipientPermissions[0] belongs to the first certificate added.  changeSecurity gives that
# recipient owner rights, so the file can be managed later.
json = chilkat2.JsonObject()
json.UpdateString("method","certificate")
json.UpdateBool("recipientPermissions[0].changeSecurity",True)

jsonOut = chilkat2.JsonObject()
success = pdf.Protection("encrypt",json,jsonOut)
if (success == False):
    print(pdf.LastErrorText)
    sys.exit()

print("method: " + jsonOut.StringOf("pending.method"))
print("algorithm: " + jsonOut.StringOf("pending.algorithm"))
print("recipients: " + str(jsonOut.SizeOfArray("pending.recipients")))

success = pdf.WriteFile("qa_output/memo_for_recipient.pdf")
if (success == False):
    print(pdf.LastErrorText)
    sys.exit()

# PreLoadCheck says how the file is protected, without loading it.
reader = chilkat2.Pdf()
info = chilkat2.JsonObject()
success = reader.PreLoadCheck("qa_output/memo_for_recipient.pdf",info)
if (success == False):
    print(reader.LastErrorText)
    sys.exit()

print("saved file, method: " + info.StringOf("method"))
print("saved file, recipients: " + str(info.SizeOfArray("recipients")))

# The recipient opens it with the certificate and its private key, here from a .pfx file.
# (On Windows, a certificate that is installed in the Windows certificate store with its private
# key is found automatically when the PDF is loaded, and SetDecryptCert is not needed for it.)
myCert = chilkat2.Cert()
success = myCert.LoadPfxFile("qa_data/pfx/recipient.pfx","pfx-password")
if (success == False):
    print(myCert.LastErrorText)
    sys.exit()

success = reader.SetDecryptCert(myCert)
if (success == False):
    print(reader.LastErrorText)
    sys.exit()

success = reader.LoadFile("qa_output/memo_for_recipient.pdf")
if (success == False):
    print(reader.LastErrorText)
    sys.exit()

empty = chilkat2.JsonObject()
loadedInfo = chilkat2.JsonObject()
success = reader.Protection("getInfo",empty,loadedInfo)
if (success == False):
    print(reader.LastErrorText)
    sys.exit()

print("opened with: " + loadedInfo.StringOf("loaded.openedWith"))
print("pages: " + str(reader.NumPages))

# Sample output:

# method: certificate
# algorithm: aes-256
# recipients: 1
# saved file, method: certificate
# saved file, recipients: 1
# opened with: certificate
# pages: 2