PureBasic

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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PureBasic

IncludeFile "CkMime.pb"

Procedure ChilkatExample()

    success.i = 0

    mime.i = CkMime::ckCreate()
    If mime.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkMime::ckLoadMimeFile(mime,"qa_data/signed.eml")
    If success = 0
        Debug CkMime::ckLastErrorText(mime)
        CkMime::ckDispose(mime)
        ProcedureReturn
    EndIf

    ;  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 = CkMime::ckVerify(mime)
    If success <> 1
        Debug CkMime::ckLastErrorText(mime)
        CkMime::ckDispose(mime)
        ProcedureReturn
    EndIf

    n.i = CkMime::ckNumSignerCerts(mime)
    i.i
    For i = 0 To n - 1
        ;  Only signers that included a signing time have one to retrieve.
        If CkMime::ckHasSignatureSigningTime(mime,i)
            signingTime.s = CkMime::ckGetSignatureSigningTimeStr(mime,i)
            If CkMime::ckLastMethodSuccess(mime) = 0
                Debug CkMime::ckLastErrorText(mime)
                CkMime::ckDispose(mime)
                ProcedureReturn
            EndIf

            Debug "Signer " + Str(i) + " signing time: " + signingTime
        EndIf

    Next


    CkMime::ckDispose(mime)


    ProcedureReturn
EndProcedure