(PHP Extension) IMAP Download and Verify Signed MIME

Downloads the original MIME of a digitally signed email and saves the .p7s signature along with other MIME parts. It then imports the email into a Chilkat email object to unwrap the S/MIME and verify the signature, and subsequently saves the attachments if they haven't been saved already.

Note: This example requires Chilkat v11.0.0 or greater.

Chilkat PHP Downloads PHP Extension for Windows, Linux, MacOS, Alpine Linux

<?php

include("chilkat.php");

$success = false;

// This example requires the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

$imap = new CkImap();

// Connect to an IMAP server.
// Use TLS
$imap->put_Ssl(true);
$imap->put_Port(993);
$success = $imap->Connect('imap.example.com');
if ($success == false) {
    print $imap->lastErrorText() . "\n";
    exit;
}

$success = $imap->Login('myLogin','myPassword');
if ($success == false) {
    print $imap->lastErrorText() . "\n";
    exit;
}

// Select an IMAP mailbox
$success = $imap->SelectMailbox('Inbox');
if ($success == false) {
    print $imap->lastErrorText() . "\n";
    exit;
}

// Download the 1st email (as MIME) in the Inbox by sequence number.
$sbMime = new CkStringBuilder();
$success = $imap->FetchSingleAsMimeSb(1,false,$sbMime);
if ($success == false) {
    print $imap->lastErrorText() . "\n";
    exit;
}

// Load it into a MIME object and check to see if it is signed
$mime = new CkMime();
$mime->LoadMimeSb($sbMime);
$alreadySavedParts = false;
if ($mime->ContainsSignedParts() == true) {

    // This will save the .p7s and other parts...
    $st = new CkStringTable();
    $success = $mime->PartsToFiles('c:/temp/qa_output',$st);
    if ($success == true) {
        $numFiles = $st->get_Count();
        $i = 0;
        while ($i < $numFiles) {
            print 'Created: ' . $st->stringAt($i) . "\n";
            $i = $i + 1;
        }

        $alreadySavedParts = true;
    }

}

// Load the MIME into an Email object.  This unwraps the security layers and verifies signatures.
$email = new CkEmail();
$email->SetFromMimeSb($sbMime);

if ($email->get_ReceivedSigned() == true) {

    print 'This email was signed.' . "\n";

    // Check to see if the signatures were verified.
    if ($email->get_SignaturesValid() == true) {
        print 'Digital signature(s) verified.' . "\n";

        print 'Signer: ' . $email->signedBy() . "\n";

        // The certificate used for signing may be obtained
        // by calling email.GetSignedByCert.
        $cert = new CkCert();
        $success = $email->LastSignerCert($i,$cert);
        if ($success == false) {
            print 'Failed to get signing certificate object.' . "\n";
        }
        else {
            print 'Signing cert: ' . $cert->subjectCN() . "\n";
        }

    }

}
else {
    print 'Digital signature verification failed.' . "\n";
}

if ($alreadySavedParts != true) {
    $email->SaveAllAttachments('c:/temp/qa_output');
}


?>