Java

Check for an S/MIME Signing Time

Demonstrates the Chilkat Mime.HasSignatureSigningTime method, which returns whether the signer at a zero-based index included a CMS signingTime signed attribute. The only argument is the signer index; use NumSignerCerts for the count.

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: A signing time records when the signer claims to have signed, which matters for auditing and for validating a certificate that has since expired. It is an optional signed attribute, so not every signature has one — this predicate lets you check before calling GetSignatureSigningTimeStr, avoiding an error for signers that omitted it. Being a signed attribute, it is covered by the signature and cannot be altered undetected.

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import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Mime;

public class ChilkatExample {

    public static void main(String[] args) {
        Mime mime = new Mime();
        try {
            mime.loadMimeFile("qa_data/signed.eml");

            // After verifying, check whether each signer included a CMS signingTime signed attribute.  The
            // only argument is the zero-based signer index.
            mime.verify();
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        int n = mime.getNumSignerCerts();
        for (int i = 0; i < n; i++) {
            if (mime.hasSignatureSigningTime(i)) {
                System.out.println("Signer " + i + " included a signing time.");
            } else {
                System.out.println("Signer " + i + " did not include a signing time.");
            }
        }
    }
}