Chilkat2-Python

CoSign PKCS7/CMS Signed Data

See more Digital Signatures Examples

Demonstrates how to add a 2nd signature to a CMS SignedData. This is to add an additional signature, SignerInfo and certificate(s) to an existing CMS signed data.

In this example, we cosign an existing pdf.p7s

Note: The CoSign method is added in Chilkat v9.5.0.89.

Chilkat2-Python

import sys
import chilkat2

success = False

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

crypt = chilkat2.Crypt2()
cert = chilkat2.Cert()

# If loading from a smart card, set the smartcard PIN.
cert.SmartCardPin = "0000"

# Load a certificate in some way, such as from a smart card.
# Chilkat provides other methods to load from a .pfx, .pem, or from the Windows certificate stores..
success = cert.LoadFromSmartcard("")
if (success == False):
    print(cert.LastErrorText)
    sys.exit()

success = crypt.SetSigningCert(cert)
if (success == False):
    print(crypt.LastErrorText)
    sys.exit()

# Load the file to be co-signed.
# NOTE:  This is to cosign a PDF file contained within a CMS (PKCS7) message.
# (In other words, the PDF is contained within the CMS SignedData, rather than the other way around
# where a CMS signature is contained within a PDF.  Use Chilkat's PDF class to sign a PDF, which is
# to embed a CMS signature within the PDF.)
bd = chilkat2.BinData()
success = bd.LoadFile("qa_data/p7s/cosign/sample.pdf.p7s")
if (success == False):
    print("Failed to load pdf.p7s input file.")
    sys.exit()

# bd2 will contain the co-signed result.
bd2 = chilkat2.BinData()
success = crypt.CoSign(bd,cert,bd2)
if (success == False):
    print(crypt.LastErrorText)
    sys.exit()

success = bd.WriteFile("qa_output/cosigned.pdf.p7s")
if (success == False):
    print("Failed to save pdf.p7s output file.")
    sys.exit()

print("Success!")