CkPython

Get an S/MIME Signing Time

Demonstrates the Chilkat Mime.GetSignatureSigningTimeStr method, which returns the CMS signingTime attribute for the signer at a zero-based index, as an RFC 822-style date string in GMT. The only argument is the signer index.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: This is the timestamp the signer asserted at signing — useful for "when was this signed" audit trails and for evaluating whether the signing certificate was valid at that moment. Because it is a signed attribute, it is tamper-evident. Guard the call with HasSignatureSigningTime, since the attribute is optional. Note it is the signer's claim, not a trusted third-party timestamp.

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import sys
import chilkat

success = False

mime = chilkat.CkMime()
success = mime.LoadMimeFile("qa_data/signed.eml")
if (success == False):
    print(mime.lastErrorText())
    sys.exit()

#  After verifying, get the CMS signingTime for each signer that has one, as an RFC 822 date string
#  in GMT.  The only argument is the zero-based signer index.
success = mime.Verify()
if (success != True):
    print(mime.lastErrorText())
    sys.exit()

n = mime.get_NumSignerCerts()

for i in range(0,n):
    #  Only signers that included a signing time have one to retrieve.
    if (mime.HasSignatureSigningTime(i)):
        signingTime = mime.getSignatureSigningTimeStr(i)
        if (mime.get_LastMethodSuccess() == False):
            print(mime.lastErrorText())
            sys.exit()

        print("Signer " + str(i) + " signing time: " + signingTime)