xmldsigjs

XMLDSIGjs

XMLDSIG is short for "XML Digital Signature". This library aims to provide an implementation of XMLDSIG in Typescript/Javascript that uses Web Crypto for cryptographic operations so it can be used both in browsers and in Node.js (when used with a polyfill like node-webcrypto-ossl or node-webcrypto-p11).

INSTALLING

npm install xmldsigjs

The npm module has build folder with the following files:

Name	Size	Description
index.js	105 Kb	CJS module with external modules
index.es.js	100 Kb	ES module with external modules
xmldsig.js	872 Kb	IIFE bundle module
xmldsig.min.js	398 Kb	minified IIFE bundled module

COMPATABILITY

CRYPTOGRAPHIC ALGORITHM SUPPORT

	SHA1	SHA2-256	SHA2-384	SHA2-512
RSASSA-PKCS1-v1_5	X	X	X	X
RSA-PSS	X	X	X	X
ECDSA	X	X	X	X
HMAC	X	X	X	X

CANONICALIZATION ALGORITHM SUPPORT

• XmlDsigC14NTransform
• XmlDsigC14NWithCommentsTransform
• XmlDsigExcC14NTransform
• XmlDsigExcC14NWithCommentsTransform
• XmlDsigEnvelopedSignatureTransform
• XmlDsigBase64Transform

PLATFORM SUPPORT

XMLDSIGjs works with any browser that supports Web Crypto. Since node does not have Web Crypto you will need a polyfill on this platform, for this reason the npm package includes node-webcrypto-ossl; browsers do not need this dependency and in those cases though it will be installed it will be ignored.

If you need to use a Hardware Security Module we have also created a polyfill for Web Crypto that supports PKCS #11. Our polyfill for this is node-webcrypto-p11.

To use node-webcrypto-ossl you need to specify you want to use it, that looks like this:

var xmldsigjs = require("xmldsigjs");
var WebCrypto = require("node-webcrypto-ossl");

xmldsigjs.Application.setEngine("OpenSSL", new WebCrypto());

The node-webcrypto-p11 polyfill will work the same way. The only difference is that you have to specify the details about your PKCS#11 device when you instansiate it:

var xmldsigjs = require("xmldsigjs");
var WebCrypto = require("node-webcrypto-p11");

xmldsigjs.Application.setEngine("PKCS11", new WebCrypto({
    library: "/path/to/pkcs11.so",
	name: "Name of PKCS11 lib",
	slot: 0,
    sessionFlags: 4, // SERIAL_SESSION
	pin: "token pin"
}));

WARNING

Using XMLDSIG is a bit like running with scissors so use it cautiously. That said it is needed for interoperability with a number of systems, for this reason, we have done this implementation.

Usage

Sign

SignedXml.Sign(algorithm: Algorithm, key: CryptoKey, data: Document, options?: OptionsSign): PromiseLike<Signature>;

Parameters

Name	Description
algorithm	Signing Algorithm
key	Signing Key
data	XML document which must be signed
options	Additional options

Options

interface OptionsSign {
    /**
     * Id of Signature
     */
    id?: string 
    /**
     * Public key for KeyInfo block
     */
    keyValue?: CryptoKey;
    /**
     * List of X509 Certificates
     */
    x509?: string[];
    /**
     * List of Reference
     * Default is Reference with hash alg SHA-256 and exc-c14n transform  
     */
    references?: OptionsSignReference[];
}

interface OptionsSignReference {
    /**
     * Id of Reference
     */
    id?: string;
    uri?: string;
    /**
     * Hash algorithm
     */
    hash: AlgorithmIdentifier;
    /**
     * List of transforms
     */
    transforms?: OptionsSignTransform[];
}

type OptionsSignTransform = "enveloped" | "c14n" | "exc-c14n" | "c14n-com" | "exc-c14n-com" | "base64";

Verify

Verify(key?: CryptoKey): PromiseLike<boolean>;

Parameters

Name	Description
key	Verifying Key. Optional. If key not set it looks for keys in KeyInfo element of Signature.

EXAMPLES

For Sign/Verify operations you will need to use a Web Crypto CryptoKey. You can see examples for an example of how to do that.

Initiating in NodeJs

"use strict";

const WebCrypto = require("node-webcrypto-ossl");
const crypto = new WebCrypto();
const XmlDSigJs = require("xmldsigjs");

XmlDSigJs.Application.setEngine("OpenSSL", crypto);

Initiating in Browser

Get the latest version form unpkg.com/xmldsigjs

<script src="https://unpkg.com/xmldsigjs@<version>/build/xmldsig.js"></script>

Creating a XMLDSIG Signature

"use strict";

let signature = new XmlDSigJs.SignedXml();

signature.Sign(                                  // Signing document
    { name: "RSASSA-PKCS1-v1_5" },                        // algorithm 
    keys.privateKey,                                      // key 
    XmlDSigJs.Parse(xml),                                 // document
    {                                                     // options
        keyValue: keys.publicKey,
        references: [
            { hash: "SHA-512", transforms: ["enveloped", "c14n"] },
        ]
    })
    .then(() => {
        console.log(signature.toString());       // <xml> document with signature
    })
    .catch(e => console.log(e));

Checking a XMLDSIG Signature

let doc = XmlDSigJs.Parse(xml);
let signature = doc.getElementsByTagNameNS("http://www.w3.org/2000/09/xmldsig#", "Signature");

let signedXml = new XmlDSigJs.SignedXml(doc);
signedXml.LoadXml(signature[0]);

signedXml.Verify()
    .then(res => {
        console.log("Signature status:", res);       // Signature status: true
    })
    .catch(e => console.log(e));

Browser Verify Example

<!DOCTYPE html>
<html>

<head>
    <meta charset="utf-8"/>
    <title>XMLDSIGjs Verify Sample</title>
</head>

<body>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/babel-polyfill/7.7.0/polyfill.min.js"></script>
    <script src="https://cdnjs.cloudflare.com/ajax/libs/asmCrypto/2.3.2/asmcrypto.all.es5.min.js"></script>
    <script src="https://cdn.rawgit.com/indutny/elliptic/master/dist/elliptic.min.js"></script>
    <script src="https://unpkg.com/webcrypto-liner@1.1.2/build/webcrypto-liner.shim.min.js"></script>
    <script src="https://unpkg.com/xmldsigjs@2.0.27/build/xmldsig.js"></script>
    <script type="text/javascript">
        fetch("signature.xml")
        .then(function(response) {
            return response.text();
        }).then(function(body) {
            var xmlString = body;

            var signedDocument = XmlDSigJs.Parse(xmlString);
            var xmlSignature = signedDocument.getElementsByTagNameNS("http://www.w3.org/2000/09/xmldsig#", "Signature");

            var signedXml = new XmlDSigJs.SignedXml(signedDocument);
            signedXml.LoadXml(xmlSignature[0]);
            signedXml.Verify()
            .then(function (res) {
                console.log((res ? "Valid" : "Invalid") + " signature");
            })
            .catch(function (e) {
                console.error(e);
            });
        })
    </script>
</body>
</html>

TESTING

In NodeJS:

npm test

In the browser

To run the browser test you need to run a test server, from the test directory run:

npm start

And the then browse to `http://localhost:3000'.

THANKS AND ACKNOWLEDGEMENT

This project takes inspiration (style, approach, design and code) from both the Mono System.Security.Cryptography.Xml implementation as well as xml-crypto.

RELATED

• Why XML Security is Broken
• XML Signature Syntax and Processing
• XML Security Algorithm Cross-Reference
• XMLDSIG HTML Signing Profile
• Canonical XML
• Exclusive XML Canonicalization
• Internet X.509 Public Key Infrastructure Time-Stamp Protocol
• PKIjs
• @peculiar/webcrypto
• node-webcrypto-ossl
• node-webcrypto-p11