Xbase++

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 nSuccess
LOCAL oMime
LOCAL n
LOCAL i
LOCAL cSigningTime

nSuccess := 0

oMime := CreateObject("Chilkat.Mime")
nSuccess := oMime:LoadMimeFile("qa_data/signed.eml")
IF (nSuccess == 0)
    ? oMime:LastErrorText
    oMime:destroy()
    RETURN
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.
nSuccess := oMime:Verify()
IF (nSuccess != 1)
    ? oMime:LastErrorText
    oMime:destroy()
    RETURN
ENDIF

n := oMime:NumSignerCerts

FOR i := 0 TO n - 1
    //  Only signers that included a signing time have one to retrieve.
    IF (oMime:HasSignatureSigningTime(i))
        cSigningTime := oMime:GetSignatureSigningTimeStr(i)
        IF (oMime:LastMethodSuccess == 0)
            ? oMime:LastErrorText
            oMime:destroy()
            RETURN
        ENDIF

        ? "Signer " + Str(i) + " signing time: " + cSigningTime
    ENDIF

NEXT

oMime:destroy()