PHP

Verify HMAC XML Digital Signature

See more XML Digital Signatures Examples

Demonstrates how to validate an XML digital signature signed with an HMAC key. Chilkat2 PHP

<?php

use Chilkat2\Http;
use Chilkat2\StringBuilder;
use Chilkat2\XmlDSig;

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

// The XML containing the Signature to be verified contains the following:

/*
 * <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 * <collection Id="root">
 *     <album>
 *         <title>Questions, unanswered</title>
 *         <artist>Steve and the flubberblubs</artist>
 *         <year>1989</year>
 *         <t:tracks xmlns:t="http://test.xades4j/tracks">
 *             <t:song length="4:05" tracknumber="1">
 *                 <t:title>What do you know?</t:title>
 *                 <t:artist>Steve and the flubberblubs</t:artist>
 *                 <t:lastplayed>2006-10-17-08:31</t:lastplayed>
 *             </t:song>
 *             <t:song length="3:45" tracknumber="2">
 *                 <t:title>Who do you know?</t:title>
 *                 <t:artist>Steve and the flubberblubs</t:artist>
 *                 <t:lastplayed>2006-10-17-08:35</t:lastplayed>
 *             </t:song>
 *             <t:song length="5:14" tracknumber="3">
 *                 <t:title>When do you know?</t:title>
 *                 <t:artist>Steve and the flubberblubs</t:artist>
 *                 <t:lastplayed>2006-10-17-08:39</t:lastplayed>
 *             </t:song>
 *             <t:song length="4:19" tracknumber="4">
 *                 <t:title>Do you know?</t:title>
 *                 <t:artist>Steve and the flubberblubs</t:artist>
 *                 <t:lastplayed>2006-10-17-08:44</t:lastplayed>
 *             </t:song>
 *         </t:tracks>
 *     </album>
 * <ds:Signature xmlns:ds="http://www.w3.org/2000/09/xmldsig#"><ds:SignedInfo><ds:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/><ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#hmac-sha256"/><ds:Reference URI="#root"><ds:Transforms><ds:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/></ds:Transforms><ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/><ds:DigestValue>rD/g8soqKz8EiPUBhEWfcQacS0ta4ULHX3dKMEH6ZoQ=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>R8dXP95VRYJBfL6d0Peogybdk27+R+JIfX8jnVu0NOI=</ds:SignatureValue></ds:Signature></collection>
 */

// The above XML is available at https://www.chilkatsoft.com/exampleData/hmacSigned.xml
// First fetch the XML..

$url = 'https://www.chilkatsoft.com/exampleData/hmacSigned.xml';
$http = new Http();
$sbXml = new StringBuilder();
try {
    $http->QuickGetSb($url, $sbXml);

    $verifier = new XmlDSig();

    // Load the XML containing the signature to be verified.
    $verifier->LoadSignatureSb($sbXml);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Provide the HMAC key
// The HMAC key for this signature is the us-ascii bytes of the string "secret",
// It can be set in any of the following ways (and also more ways not shown here..)
$verifier->SetHmacKey('secret', 'ascii');
// or
$verifier->SetHmacKey('c2VjcmV0', 'base64');
// or
$verifier->SetHmacKey('736563726574', 'hex');

// Verify the signature
try {
    $verifier->VerifySignature(true);
    $bVerified = true;
} catch (\Chilkat2\Exception $e) {
    $bVerified = false;
}
echo 'Signature verified = ', ($bVerified ? 'true' : 'false'), "\n";