(PHP ActiveX) Verify DomainKey-Signature Headers in Downloaded Email

Chilkat ActiveX Downloads ActiveX for 32-bit and 64-bit Windows Note: The php_com_dotnet.dll may need to be enabled inside of php.ini.

<?php

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

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Imap')
$imap = new COM("Chilkat.Imap");

// Connect to an IMAP server, login, select mailbox..
// Use TLS 
$imap->Ssl = 1;
$imap->Port = 993;
$success = $imap->Connect('imap.someMailServer.com');
if ($success == 1) {
    $success = $imap->Login('myLogin','myPassword');
    if ($success == 1) {
        $success = $imap->SelectMailbox('Inbox');
    }

}

if ($success != 1) {
    print $imap->LastErrorText . "\n";
    exit;
}

// Note: DKIM-Signatures are much more common than DomainKey-Signature
// See DKIM-Signature Verify Sample.

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.Dkim')
$dkim = new COM("Chilkat.Dkim");

// Download a max of 10 emails and verify any DomainKey-Signature headers
// that are present.

// Download emails by sequence numbers (not UIDs).
$bUid = 0;

$n = $imap->NumMessages;
if ($n > 50) {
    $n = 50;
}

// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.JsonObject')
$json = new COM("Chilkat.JsonObject");
$json->EmitCompact = 0;

// To verify DomainKey-Signature headers, we need the exact unmodified MIME bytes of each email.
// For versions of Chilkat < 10.0.0, use new COM('Chilkat_9_5_0.Chilkat.BinData')
$mimeData = new COM("Chilkat.BinData");
$seqNum = 1;
while ($seqNum <= $n) {
    // The FetchSingleBd method was introduced in v9.5.0.76
    $success = $imap->FetchSingleBd($seqNum,$bUid,$mimeData);
    if ($success != 1) {
        print $imap->LastErrorText . "\n";
        exit;
    }

    // Note: DKIM-Signatures are much more common than DomainKey-Signature
    // See DKIM-Signature Verify Sample.

    // Get the number of DomainKey-Signature headers.
    $numSigs = $dkim->NumDomainKeySigs($mimeData);

    // Verify each..
    $j = 0;
    while ($j < $numSigs) {
        print '------ DomainKey Signature ' . $j . "\n";

        $success = $dkim->DomainKeyVerify($j,$mimeData);
        if ($success != 1) {
            print 'Not valid.' . "\n";
            print $dkim->LastErrorText . "\n";
        }
        else {
            print 'valid.' . "\n";
        }

        // Show the additional information about the signature verification
        $json->Load($dkim->VerifyInfo);
        print $json->emit() . "\n";

        // The JSON contains information such as this:

        // 	{
        // 	  "domain": "amazonses.com",
        // 	  "selector": "7v7vs6w47njt4pimodk5mmttbegzsi6n",
        // 	  "publicKey": "MIGfMA0GCSqG...v2GvWPqGHz6uqeQIDAQAB",
        // 	  "canonicalization": "relaxed/simple",
        // 	  "algorithm": "rsa-sha256",
        // 	  "signedHeaders": "Subject:From:To:Date:Mime-Version:Content-Type:References:Message-Id:Feedback-ID",
        // 	  "verified": "yes"
        // 	}

        $j = $j + 1;
    }

    $seqNum = $seqNum + 1;
}

$success = $imap->Disconnect();

?>