Visual FoxPro

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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LOCAL lnSuccess
LOCAL loMime
LOCAL n
LOCAL i
LOCAL lcSigningTime

lnSuccess = 0

loMime = CreateObject('Chilkat.Mime')
lnSuccess = loMime.LoadMimeFile("qa_data/signed.eml")
IF (lnSuccess = 0) THEN
    ? loMime.LastErrorText
    RELEASE loMime
    CANCEL
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.
lnSuccess = loMime.Verify()
IF (lnSuccess <> 1) THEN
    ? loMime.LastErrorText
    RELEASE loMime
    CANCEL
ENDIF

n = loMime.NumSignerCerts

FOR i = 0 TO n - 1
    *  Only signers that included a signing time have one to retrieve.
    IF (loMime.HasSignatureSigningTime(i)) THEN
        lcSigningTime = loMime.GetSignatureSigningTimeStr(i)
        IF (loMime.LastMethodSuccess = 0) THEN
            ? loMime.LastErrorText
            RELEASE loMime
            CANCEL
        ENDIF

        ? "Signer " + STR(i) + " signing time: " + lcSigningTime
    ENDIF

NEXT

RELEASE loMime