Perl

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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Perl

use chilkat();

$success = 0;

$mime = chilkat::CkMime->new();
$success = $mime->LoadMimeFile("qa_data/signed.eml");
if ($success == 0) {
    print $mime->lastErrorText() . "\r\n";
    exit;
}

#  After verifying, check whether each signer included a CMS signingTime signed attribute.  The
#  only argument is the zero-based signer index.
$success = $mime->Verify();
if ($success != 1) {
    print $mime->lastErrorText() . "\r\n";
    exit;
}

$n = $mime->get_NumSignerCerts();

for ($i = 0; $i <= $n - 1; $i++) {
    if ($mime->HasSignatureSigningTime($i)) {
        print "Signer " . $i . " included a signing time." . "\r\n";
    }
    else {
        print "Signer " . $i . " did not include a signing time." . "\r\n";
    }

}