PHP

Create XML Digital Signature using a ECDSA Key

See more XML Digital Signatures Examples

Demonstrates how to create an XML digital signature using a ECDSA key.

This example requires Chilkat v9.5.0.69 or greater.

Chilkat2 PHP

<?php

use Chilkat2\Http;
use Chilkat2\PrivateKey;
use Chilkat2\StringBuilder;
use Chilkat2\XmlDSig;
use Chilkat2\XmlDSigGen;

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

// The SOAP XML to be signed in this example contains the following:

/*
 * <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
 * <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
 *     <SOAP-ENV:Header>
 *         <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" SOAP-ENV:mustUnderstand="1"></wsse:Security>
 *     </SOAP-ENV:Header>
 *     <SOAP-ENV:Body xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12" SOAP-SEC:id="Body">
 *         <z:FooBar xmlns:z="http://example.com" />
 *     </SOAP-ENV:Body>
 * </SOAP-ENV:Envelope>
 *
 */

// The above XML is available at https://www.chilkatsoft.com/exampleData/soapToSign.xml
// Fetch the XML and then sign it..

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

    // This example uses an ECDSA private key for signing.
    // There are many ways to load an ECDSA private key using Chilkat.  This example
    // will load from an unencrypted PEM file.

    // For your convenience, Chilkat put this sample ECDSA PEM here:  https://www.chilkatsoft.com/exampleData/secp256r1-key.zip
    $ecKey = new PrivateKey();
    $ecKey->LoadPemFile('qa_data/ecc/secp256r1-key.pem');

    // To create the XML digital signature (i.e. embed the signature within
    // the SOAP XML), we specify what is desired, and then call the method to
    // create the XML signature.
    //
    // For example, the application must provide the following:
    //     - Where to put the signature.
    //     - What to sign.
    //     - The algorithms to be used.
    //     - The key to be used for signing.
    //

    $xmlSigGen = new XmlDSigGen();

    // In this example, the Signature will be placed within the wsse:Security element.
    // To specify the location, set the SigLocation property to the XML path to this element,
    // using vertical bar characters to separate tags.
    $xmlSigGen->SigLocation = 'SOAP-ENV:Envelope|SOAP-ENV:Header|wsse:Security';

    // An XML digital signature contains one or more references.  A given reference
    // can be a same-document reference (to an XML fragment), or an external reference.
    // This example will add a single same-document reference.  We'll add a reference to the XML fragment
    // at SOAP-ENV:Body, which is indicated by providing the value of the "Id" attribute (where "Id" is case
    // insensitive).  For each same-document reference, we must also indicate the hash algorithm and XML canonicalization
    // algorithm to be used.  For this example we'll choose SHA-256 and Exclusive XML Canonicalization.
    $xmlSigGen->AddSameDocRef('Body', 'sha256', 'EXCL_C14N', '', '');

    // Let's provide the ECDSA key to be used for signing:
    $xmlSigGen->SetPrivateKey($ecKey);

    // We're leaving the following properties at their default values:
    //
    //    - SigNamespacePrefix (default is "ds")
    //    - SignedInfoCanonAlg  (default is EXCL_C14N)
    //    - SignedInfoDigestMethod (default is sha256)
    //    - KeyInfoType (default is "KeyValue", where the ECDSA public key is included in the Signature)

    // Note: Each Reference specifies its own algorithms for XML canonicalization and hashing.
    // The SignedInfo part also has specified hash and canonicalization algorithms, which may be different
    // than the algorithms used in the References.
    // In this example, we use Exclusive XML Canonicalization and SHA-256 throughout.

    // Finally, we're going to set one property that's optional, but commonly used.
    // It's the SignedInfoPrefixList.  In this case, we're using Exclusive Canonicalization, and the signature
    // will be placed in a location within the XML document where namespace prefixes are used in the ancestors.
    // Specifically, the "wsse" and "SOAP-ENV" namespace prefixes are used.
    $xmlSigGen->SignedInfoPrefixList = 'wsse SOAP-ENV';

    // OK, everything's specified, so let's create the XML digital signature:
    // This in-place signs the XML.  If successful, sbSoapXml will contain the
    // XML with the digital signature at the specified location.
    $xmlSigGen->CreateXmlDSigSb($sbSoapXml);
} catch (\Chilkat2\Exception $e) {
    echo $e->getMessage(), "\n";
    exit;
}

// Examine the signed SOAP XML:
echo $sbSoapXml->GetAsString(), "\n";

// This is the signed SOAP XML.
// Chilkat emits the Signature in compact form on a single line.  Whitespace in XML signatures
// matters.  Chilkat's opinion is that writing the Signature without whitespace minimizes the chance
// for problems with whatever software might be verifying the signature.

/*
 * <?xml version="1.0" encoding="UTF-8" standalone="no" ?>
 * <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/">
 *     <SOAP-ENV:Header>
 *         <wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd" SOAP-ENV:mustUnderstand="1"><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#"><InclusiveNamespaces xmlns="http://www.w3.org/2001/10/xml-exc-c14n#" PrefixList="wsse SOAP-ENV"/></ds:CanonicalizationMethod><ds:SignatureMethod Algorithm="http://www.w3.org/2001/04/xmldsig-more#ecdsa-sha256"/><ds:Reference URI="#Body"><ds:Transforms><ds:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/></ds:Transforms><ds:DigestMethod Algorithm="http://www.w3.org/2001/04/xmlenc#sha256"/><ds:DigestValue>OwgHPZNfDkXnZsjpfzXqAcT3RV3HzmTsEy2bP44FJ0M=</ds:DigestValue></ds:Reference></ds:SignedInfo><ds:SignatureValue>jmPSGgtirHSjjcs/o0NIDwwvy4aFBCEosSN+XP5NLVuGpRYnS2EM7mItiw6TKmESAoJYV23ZN4pZ9BFRKSvZqw==</ds:SignatureValue><ds:KeyInfo><ds:KeyValue><ds:ECKeyValue xmlns="http://www.w3.org/2009/xmldsig11#"><ds:NamedCurve URI="urn:oid:1.2.840.10045.3.1.7" /><ds:PublicKey>BOVKaiLPKEDChhkA64UEBOXTv/VFHnhrUPN+bXqCvEl7rroAYpH5tKzbiGTtMSlp4JO9Pxg44zeX7EoWDvOrpD0=</ds:PublicKey></ds:ECKeyValue></ds:KeyValue></ds:KeyInfo></ds:Signature></wsse:Security>
 *     </SOAP-ENV:Header>
 *     <SOAP-ENV:Body xmlns:SOAP-SEC="http://schemas.xmlsoap.org/soap/security/2000-12" SOAP-SEC:id="Body">
 *         <z:FooBar xmlns:z="http://example.com" />
 *     </SOAP-ENV:Body>
 * </SOAP-ENV:Envelope>
 */

// The above signed XML contains the ECDSA public key in the ECKeyValue fragment (within the ds:KeyInfo).
// The signature can easily be verified like this:

$verifier = new XmlDSig();

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

try {
    $verifier->VerifySignature(true);
    $bVerified = true;
} catch (\Chilkat2\Exception $e) {
    $bVerified = false;
}
if (!$bVerified) {
    echo $verifier->LastErrorText, "\n";
}

echo 'Signature verified = ', ($bVerified ? 'true' : 'false'), "\n";