C++

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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C++

#include <CkMime.h>

void ChilkatSample(void)
    {
    bool success = false;

    CkMime mime;
    success = mime.LoadMimeFile("qa_data/signed.eml");
    if (success == false) {
        std::cout << mime.lastErrorText() << "\r\n";
        return;
    }

    //  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) {
        std::cout << mime.lastErrorText() << "\r\n";
        return;
    }

    int n = mime.get_NumSignerCerts();
    int i;
    for (i = 0; i <= n - 1; i++) {
        //  Only signers that included a signing time have one to retrieve.
        if (mime.HasSignatureSigningTime(i)) {
            const char *signingTime = mime.getSignatureSigningTimeStr(i);
            if (mime.get_LastMethodSuccess() == false) {
                std::cout << mime.lastErrorText() << "\r\n";
                return;
            }

            std::cout << "Signer " << i << " signing time: " << signingTime << "\r\n";
        }

    }
    }