Add XmlDSigVerifier wrapper for SignedXml

.nvmrc

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+v22.16.0

README.md

@@ -209,6 +209,31 @@ Note:
 
 The xml-crypto api requires you to supply it separately the xml signature ("<Signature>...</Signature>", in loadSignature) and the signed xml (in checkSignature). The signed xml may or may not contain the signature in it, but you are still required to supply the signature separately.
 
+### Secure Verification with XmlDSigVerifier (Recommended)
+
+For a more secure and streamlined verification experience, use the `XmlDSigVerifier` class. It provides built-in checks for certificate expiration, truststore validation, and easier configuration.
+
+```javascript
+const { XmlDSigVerifier } = require("xml-crypto");
+const fs = require("fs");
+
+const xml = fs.readFileSync("signed.xml", "utf-8");
+const publicCert = fs.readFileSync("client_public.pem", "utf-8");
+
+const result = XmlDSigVerifier.verifySignature(xml, {
+  keySelector: { publicCert: publicCert },
+});
+
+if (result.success) {
+  console.log("Valid signature!");
+  console.log("Signed content:", result.signedReferences);
+} else {
+  console.error("Invalid signature:", result.error);
+}
+```
+
+For detailed usage instructions, see [XMLDSIG_VERIFIER.md](./XMLDSIG_VERIFIER.md).
+
 ### Caring for Implicit transform
 
 If you fail to verify signed XML, then one possible cause is that there are some hidden implicit transforms(#).  

XMLDSIG_VERIFIER.md

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+# XmlDSigVerifier Usage Guide
+
+`XmlDSigVerifier` provides a focused, secure, and easy-to-use API for verifying XML signatures. It is designed to replace direct usage of `SignedXml` for verification scenarios, offering built-in security checks and a simplified configuration.
+
+## Features
+
+- **Type-Safe Configuration:** Explicit options for different key retrieval strategies (Public Certificate, KeyInfo, Shared Secret).
+- **Enhanced Security:** Built-in checks for certificate expiration, truststore validation, and limits on transform complexity.
+- **Algorithm Allow-Lists:** Restrict which signature, hash, transform, and canonicalization algorithms are accepted.
+- **Flexible Error Handling:** Choose between throwing errors or returning a result object.
+- **Reusable Instances:** Create a verifier once and use it to verify multiple documents.
+
+## Installation
+
+Ensure you have `xml-crypto` installed:
+
+```bash
+npm install xml-crypto
+```
+
+## Imports
+
+```typescript
+import {
+  XmlDSigVerifier,
+  XMLDSIG_URIS,
+  // Algorithm classes (for customizing allowed algorithms)
+  Sha1,
+  Sha256,
+  Sha512,
+  RsaSha1,
+  RsaSha256,
+  RsaSha256Mgf1,
+  RsaSha512,
+  HmacSha1,
+  EnvelopedSignature,
+  C14nCanonicalization,
+  C14nCanonicalizationWithComments,
+  ExclusiveCanonicalization,
+  ExclusiveCanonicalizationWithComments,
+  // Types (optional, for TypeScript users)
+  type XmlDSigVerifierOptions,
+  type XmlDsigVerificationResult,
+} from "xml-crypto";
+```
+
+`XMLDSIG_URIS` provides constants for all supported algorithm URIs:
+
+```typescript
+XMLDSIG_URIS.SIGNATURE_ALGORITHMS.RSA_SHA256; // "http://www.w3.org/2001/04/xmldsig-more#rsa-sha256"
+XMLDSIG_URIS.HASH_ALGORITHMS.SHA256; // "http://www.w3.org/2001/04/xmlenc#sha256"
+XMLDSIG_URIS.CANONICALIZATION_ALGORITHMS.EXCLUSIVE_C14N; // "http://www.w3.org/2001/10/xml-exc-c14n#"
+XMLDSIG_URIS.TRANSFORM_ALGORITHMS.ENVELOPED_SIGNATURE; // "http://www.w3.org/2000/09/xmldsig#enveloped-signature"
+XMLDSIG_URIS.NAMESPACES.ds; // "http://www.w3.org/2000/09/xmldsig#"
+```
+
+## Quick Start
+
+### 1. Verifying with a Public Certificate
+
+If you already have the public certificate or key and want to verify a document signed with the corresponding private key:
+
+```typescript
+import { XmlDSigVerifier } from "xml-crypto";
+import * as fs from "fs";
+
+const xml = fs.readFileSync("signed_document.xml", "utf-8");
+const publicCert = fs.readFileSync("public_key.pem", "utf-8");
+
+const result = XmlDSigVerifier.verifySignature(xml, {
+  keySelector: { publicCert: publicCert },
+});
+
+if (result.success) {
+  console.log("Signature valid!");
+  // Access the signed content securely
+  console.log("Signed references:", result.signedReferences);
+} else {
+  console.error("Verification failed:", result.error);
+}
+```
+
+### 2. Verifying using KeyInfo (with Truststore)
+
+When the XML document contains the certificate in a `<KeyInfo>` element, you can verify it while ensuring the certificate is trusted and valid.
+
+```typescript
+import { XmlDSigVerifier, SignedXml } from "xml-crypto";
+import * as fs from "fs";
+
+const xml = fs.readFileSync("signed_with_keyinfo.xml", "utf-8");
+const trustedRootCert = fs.readFileSync("root_ca.pem", "utf-8");
+
+const result = XmlDSigVerifier.verifySignature(xml, {
+  keySelector: {
+    // Extract the certificate from KeyInfo
+    getCertFromKeyInfo: (keyInfo) => SignedXml.getCertFromKeyInfo(keyInfo),
+  },
+  security: {
+    // Ensure the certificate is trusted by your root CA
+    truststore: [trustedRootCert],
+    // Automatically check if the certificate is expired
+    checkCertExpiration: true,
+  },
+});
+
+if (result.success) {
+  console.log("Signature is valid and trusted.");
+} else {
+  console.log("Verification failed:", result.error);
+}
+```
+
+### 3. Verifying with a Shared Secret (HMAC)
+
+For documents signed with HMAC (symmetric key):
+
+```typescript
+import { XmlDSigVerifier } from "xml-crypto";
+
+const result = XmlDSigVerifier.verifySignature(xml, {
+  keySelector: { sharedSecretKey: "my-shared-secret" },
+});
+
+if (result.success) {
+  console.log("HMAC signature valid!");
+}
+```
+
+Note: When using `sharedSecretKey`, HMAC signature algorithms are enabled and asymmetric algorithms are disabled by default to prevent key confusion attacks.
+
+## Advanced Usage
+
+### Reusing the Verifier Instance
+
+For better performance when verifying multiple documents with the same configuration, create an instance of `XmlDSigVerifier`:
+
+```typescript
+const verifier = new XmlDSigVerifier({
+  keySelector: { publicCert: myPublicCert },
+  security: { maxTransforms: 2 },
+});
+
+const result1 = verifier.verifySignature(xml1);
+const result2 = verifier.verifySignature(xml2);
+```
+
+### Verification Options
+
+The `verifySignature` method accepts an options object with the following structure:
+
+```typescript
+interface XmlDSigVerifierOptions {
+  // STRATEGY: Choose one of the following key selectors
+  keySelector:
+    | { publicCert: KeyLike } // Direct public key/cert
+    | { getCertFromKeyInfo: (node?: Node | null) => string | null } // Extract from XML
+    | { sharedSecretKey: KeyLike }; // HMAC shared secret
+
+  // CONFIGURATION
+  idAttributes?: VerificationIdAttributeType[]; // Default: ["Id", "ID", "id"]
+  implicitTransforms?: ReadonlyArray<TransformAlgorithmURI>; // Hidden transforms to apply
+  throwOnError?: boolean; // Default: false (returns result object)
+
+  // SECURITY
+  security?: {
+    maxTransforms?: number; // Limit transforms per reference (DoS protection). Default: 4
+    signatureAlgorithms?: Array<new () => SignatureAlgorithm>; // Allowed signature algorithms
+    hashAlgorithms?: Array<new () => HashAlgorithm>; // Allowed hash algorithms
+    transformAlgorithms?: Array<new () => TransformAlgorithm>; // Allowed transform algorithms
+    canonicalizationAlgorithms?: Array<new () => CanonicalizationAlgorithm>; // Allowed canonicalization algorithms
+
+    // KeyInfo-only options (only available with getCertFromKeyInfo selector):
+    checkCertExpiration?: boolean; // Check NotBefore/NotAfter. Default: true
+    truststore?: Array<string | Buffer | X509Certificate>; // Trusted CA certificates
+  };
+}
+```
+
+#### Extending Defaults with Custom Algorithms
+
+Algorithm lists are simple arrays of constructor classes. Each class provides its own URI via `getAlgorithmName()`, eliminating the need for manual URI keys. To add a custom algorithm alongside the defaults, spread the default array:
+
+```typescript
+import { XmlDSigVerifier } from "xml-crypto";
+import { MyCustomHashAlgorithm } from "./my-algorithms";
+
+const result = XmlDSigVerifier.verifySignature(xml, {
+  keySelector: { publicCert },
+  security: {
+    hashAlgorithms: [...XmlDSigVerifier.defaultHashAlgorithms, MyCustomHashAlgorithm],
+  },
+});
+```
+
+### ID Attributes
+
+The `idAttributes` option controls which XML attributes are treated as element identifiers when resolving signature references.
+
+```typescript
+// Simple string format (matches attribute name in any namespace)
+idAttributes: ["Id", "ID", "customId"];
+
+// Namespaced format for stricter matching
+idAttributes: [
+  { localName: "Id", namespaceUri: "http://example.com/ns" }, // Match only in specific namespace
+  { localName: "Id", namespaceUri: null }, // Match only non-namespaced attributes
+  { localName: "Id" }, // Match regardless of namespace (same as string)
+];
+```
+
+### Implicit Transforms
+
+If you fail to verify signed XML, one possible cause is hidden implicit transforms that were applied during signing but not listed in the signature. Use `implicitTransforms` to specify them:
+
+```typescript
+const result = XmlDSigVerifier.verifySignature(xml, {
+  keySelector: { publicCert },
+  implicitTransforms: [XMLDSIG_URIS.CANONICALIZATION_ALGORITHMS.C14N],
+});
+```
+
+### Error Handling
+
+By default, `verifySignature` returns a result object. If you prefer to handle exceptions:
+
+```typescript
+try {
+  const result = XmlDSigVerifier.verifySignature(xml, {
+    keySelector: { publicCert },
+    throwOnError: true, // Will throw Error on failure
+  });
+  // If code reaches here, signature is valid
+} catch (e) {
+  console.error("Signature invalid:", e.message);
+}
+```
+
+### Result Types
+
+The verification result is a discriminated union:
+
+```typescript
+// On success
+{
+  success: true,
+  signedReferences: string[]  // Canonicalized XML content that was signed
+}
+
+// On failure (when throwOnError is false)
+{
+  success: false,
+  error: string  // Description of what went wrong
+}
+```
+
+### Handling Multiple Signatures
+
+If a document contains multiple signatures, you must specify which one to verify by passing the signature node.
+
+```typescript
+import { DOMParser } from "@xmldom/xmldom";
+
+const doc = new DOMParser().parseFromString(xml, "application/xml");
+const signatures = doc.getElementsByTagNameNS(XMLDSIG_URIS.NAMESPACES.ds, "Signature");
+
+// Verify the second signature
+const result = XmlDSigVerifier.verifySignature(
+  xml,
+  {
+    keySelector: { publicCert },
+  },
+  signatures[1],
+);
+```

package.json

@@ -40,7 +40,7 @@
   "dependencies": {
     "@xmldom/is-dom-node": "^1.0.1",
     "@xmldom/xmldom": "^0.8.10",
-    "xpath": "^0.0.33"
+    "xpath": "^0.0.34"
   },
   "devDependencies": {
     "@cjbarth/github-release-notes": "^4.2.0",