Implement crypto adapter pattern for platform independence

Adds CryptoAdapter interface with WebCryptoAdapter (browser) and
NodeCryptoAdapter (Node.js 19+) implementations.

Changes:
- Created crypto-adapter.ts interface
- Created web-crypto-adapter.ts for browser environments
- Created node-crypto-adapter.ts for Node.js environments
- Updated RondevuAPI to accept optional CryptoAdapter
- Updated Rondevu class to pass crypto adapter through
- Exported adapters and types in index.ts
- Updated README with platform support documentation
- Bumped version to 0.15.0

This allows the client library to work in both browser and Node.js
environments by providing platform-specific crypto implementations.

Example usage in Node.js:
  import { Rondevu, NodeCryptoAdapter } from '@xtr-dev/rondevu-client'

  const rondevu = new Rondevu({
    apiUrl: 'https://api.ronde.vu',
    cryptoAdapter: new NodeCryptoAdapter()
  })

🤖 Generated with Claude Code
https://claude.com/claude-code

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/api.ts

@@ -2,17 +2,10 @@
  * Rondevu API Client - RPC interface
  */
 
-import * as ed25519 from '@noble/ed25519'
+import { CryptoAdapter, Keypair } from './crypto-adapter.js'
+import { WebCryptoAdapter } from './web-crypto-adapter.js'
 
-// Set SHA-512 hash function for ed25519 (required in @noble/ed25519 v3+)
-ed25519.hashes.sha512Async = async (message: Uint8Array) => {
-    return new Uint8Array(await crypto.subtle.digest('SHA-512', message as BufferSource))
-}
-
-export interface Keypair {
-    publicKey: string
-    privateKey: string
-}
+export type { Keypair } from './crypto-adapter.js'
 
 export interface OfferRequest {
     sdp: string
@@ -47,22 +40,6 @@ export interface IceCandidate {
     createdAt: number
 }
 
-/**
- * Helper: Convert Uint8Array to base64 string
- */
-function bytesToBase64(bytes: Uint8Array): string {
-    const binString = Array.from(bytes, byte => String.fromCodePoint(byte)).join('')
-    return btoa(binString)
-}
-
-/**
- * Helper: Convert base64 string to Uint8Array
- */
-function base64ToBytes(base64: string): Uint8Array {
-    const binString = atob(base64)
-    return Uint8Array.from(binString, char => char.codePointAt(0)!)
-}
-
 /**
  * RPC request format
  */
@@ -87,11 +64,17 @@ interface RpcResponse {
  * RondevuAPI - RPC-based API client for Rondevu signaling server
  */
 export class RondevuAPI {
+    private crypto: CryptoAdapter
+
     constructor(
         private baseUrl: string,
         private username: string,
-        private keypair: Keypair
-    ) {}
+        private keypair: Keypair,
+        cryptoAdapter?: CryptoAdapter
+    ) {
+        // Use WebCryptoAdapter by default (browser environment)
+        this.crypto = cryptoAdapter || new WebCryptoAdapter()
+    }
 
     /**
      * Generate authentication parameters for RPC calls
@@ -105,7 +88,7 @@ export class RondevuAPI {
             ? `${method}:${this.username}:${params}:${timestamp}`
             : `${method}:${this.username}:${timestamp}`
 
-        const signature = await RondevuAPI.signMessage(message, this.keypair.privateKey)
+        const signature = await this.crypto.signMessage(message, this.keypair.privateKey)
 
         return { message, signature }
     }
@@ -163,47 +146,38 @@ export class RondevuAPI {
 
     /**
      * Generate an Ed25519 keypair for username claiming and service publishing
+     * @param cryptoAdapter - Optional crypto adapter (defaults to WebCryptoAdapter)
      */
-    static async generateKeypair(): Promise<Keypair> {
-        const privateKey = ed25519.utils.randomSecretKey()
-        const publicKey = await ed25519.getPublicKeyAsync(privateKey)
-
-        return {
-            publicKey: bytesToBase64(publicKey),
-            privateKey: bytesToBase64(privateKey),
-        }
+    static async generateKeypair(cryptoAdapter?: CryptoAdapter): Promise<Keypair> {
+        const adapter = cryptoAdapter || new WebCryptoAdapter()
+        return await adapter.generateKeypair()
     }
 
     /**
      * Sign a message with an Ed25519 private key
+     * @param cryptoAdapter - Optional crypto adapter (defaults to WebCryptoAdapter)
      */
-    static async signMessage(message: string, privateKeyBase64: string): Promise<string> {
-        const privateKey = base64ToBytes(privateKeyBase64)
-        const encoder = new TextEncoder()
-        const messageBytes = encoder.encode(message)
-        const signature = await ed25519.signAsync(messageBytes, privateKey)
-
-        return bytesToBase64(signature)
+    static async signMessage(
+        message: string,
+        privateKeyBase64: string,
+        cryptoAdapter?: CryptoAdapter
+    ): Promise<string> {
+        const adapter = cryptoAdapter || new WebCryptoAdapter()
+        return await adapter.signMessage(message, privateKeyBase64)
     }
 
     /**
      * Verify an Ed25519 signature
+     * @param cryptoAdapter - Optional crypto adapter (defaults to WebCryptoAdapter)
      */
     static async verifySignature(
         message: string,
         signatureBase64: string,
-        publicKeyBase64: string
+        publicKeyBase64: string,
+        cryptoAdapter?: CryptoAdapter
     ): Promise<boolean> {
-        try {
-            const signature = base64ToBytes(signatureBase64)
-            const publicKey = base64ToBytes(publicKeyBase64)
-            const encoder = new TextEncoder()
-            const messageBytes = encoder.encode(message)
-
-            return await ed25519.verifyAsync(signature, messageBytes, publicKey)
-        } catch {
-            return false
-        }
+        const adapter = cryptoAdapter || new WebCryptoAdapter()
+        return await adapter.verifySignature(message, signatureBase64, publicKeyBase64)
     }
 
     // ============================================

src/crypto-adapter.ts

@@ -0,0 +1,48 @@
+/**
+ * Crypto adapter interface for platform-independent cryptographic operations
+ */
+
+export interface Keypair {
+    publicKey: string
+    privateKey: string
+}
+
+/**
+ * Platform-independent crypto adapter interface
+ * Implementations provide platform-specific crypto operations
+ */
+export interface CryptoAdapter {
+    /**
+     * Generate an Ed25519 keypair
+     */
+    generateKeypair(): Promise<Keypair>
+
+    /**
+     * Sign a message with an Ed25519 private key
+     */
+    signMessage(message: string, privateKeyBase64: string): Promise<string>
+
+    /**
+     * Verify an Ed25519 signature
+     */
+    verifySignature(
+        message: string,
+        signatureBase64: string,
+        publicKeyBase64: string
+    ): Promise<boolean>
+
+    /**
+     * Convert Uint8Array to base64 string
+     */
+    bytesToBase64(bytes: Uint8Array): string
+
+    /**
+     * Convert base64 string to Uint8Array
+     */
+    base64ToBytes(base64: string): Uint8Array
+
+    /**
+     * Generate random bytes
+     */
+    randomBytes(length: number): Uint8Array
+}

src/index.ts

@@ -7,6 +7,10 @@ export { Rondevu } from './rondevu.js'
 export { RondevuAPI } from './api.js'
 export { RondevuSignaler } from './rondevu-signaler.js'
 
+// Export crypto adapters
+export { WebCryptoAdapter } from './web-crypto-adapter.js'
+export { NodeCryptoAdapter } from './node-crypto-adapter.js'
+
 // Export types
 export type {
     Signaler,
@@ -26,3 +30,5 @@ export type { RondevuOptions, PublishServiceOptions } from './rondevu.js'
 
 export type { PollingConfig } from './rondevu-signaler.js'
 
+export type { CryptoAdapter } from './crypto-adapter.js'
+

src/node-crypto-adapter.ts

@@ -0,0 +1,98 @@
+/**
+ * Node.js Crypto adapter for Node.js environments
+ * Requires Node.js 19+ or Node.js 18 with --experimental-global-webcrypto flag
+ */
+
+import * as ed25519 from '@noble/ed25519'
+import { CryptoAdapter, Keypair } from './crypto-adapter.js'
+
+/**
+ * Node.js Crypto implementation using Node.js built-in APIs
+ * Uses Buffer for base64 encoding and crypto.randomBytes for random generation
+ *
+ * Requirements:
+ * - Node.js 19+ (crypto.subtle available globally)
+ * - OR Node.js 18 with --experimental-global-webcrypto flag
+ *
+ * @example
+ * ```typescript
+ * import { RondevuAPI } from '@xtr-dev/rondevu-client'
+ * import { NodeCryptoAdapter } from '@xtr-dev/rondevu-client/node'
+ *
+ * const api = new RondevuAPI(
+ *   'https://signal.example.com',
+ *   'alice',
+ *   keypair,
+ *   new NodeCryptoAdapter()
+ * )
+ * ```
+ */
+export class NodeCryptoAdapter implements CryptoAdapter {
+    constructor() {
+        // Set SHA-512 hash function for ed25519 using Node's crypto.subtle
+        if (typeof crypto === 'undefined' || !crypto.subtle) {
+            throw new Error(
+                'crypto.subtle is not available. ' +
+                'Node.js 19+ is required, or Node.js 18 with --experimental-global-webcrypto flag'
+            )
+        }
+
+        ed25519.hashes.sha512Async = async (message: Uint8Array) => {
+            const hash = await crypto.subtle.digest('SHA-512', message as BufferSource)
+            return new Uint8Array(hash)
+        }
+    }
+
+    async generateKeypair(): Promise<Keypair> {
+        const privateKey = ed25519.utils.randomSecretKey()
+        const publicKey = await ed25519.getPublicKeyAsync(privateKey)
+
+        return {
+            publicKey: this.bytesToBase64(publicKey),
+            privateKey: this.bytesToBase64(privateKey),
+        }
+    }
+
+    async signMessage(message: string, privateKeyBase64: string): Promise<string> {
+        const privateKey = this.base64ToBytes(privateKeyBase64)
+        const encoder = new TextEncoder()
+        const messageBytes = encoder.encode(message)
+        const signature = await ed25519.signAsync(messageBytes, privateKey)
+
+        return this.bytesToBase64(signature)
+    }
+
+    async verifySignature(
+        message: string,
+        signatureBase64: string,
+        publicKeyBase64: string
+    ): Promise<boolean> {
+        try {
+            const signature = this.base64ToBytes(signatureBase64)
+            const publicKey = this.base64ToBytes(publicKeyBase64)
+            const encoder = new TextEncoder()
+            const messageBytes = encoder.encode(message)
+
+            return await ed25519.verifyAsync(signature, messageBytes, publicKey)
+        } catch {
+            return false
+        }
+    }
+
+    bytesToBase64(bytes: Uint8Array): string {
+        // Node.js Buffer provides native base64 encoding
+        // @ts-expect-error - Buffer is available in Node.js but not in browser TypeScript definitions
+        return Buffer.from(bytes).toString('base64')
+    }
+
+    base64ToBytes(base64: string): Uint8Array {
+        // Node.js Buffer provides native base64 decoding
+        // @ts-expect-error - Buffer is available in Node.js but not in browser TypeScript definitions
+        return new Uint8Array(Buffer.from(base64, 'base64'))
+    }
+
+    randomBytes(length: number): Uint8Array {
+        // Use Web Crypto API's getRandomValues (available in Node 19+)
+        return crypto.getRandomValues(new Uint8Array(length))
+    }
+}

src/rondevu.ts

@@ -1,9 +1,11 @@
 import { RondevuAPI, Keypair, Service, ServiceRequest, IceCandidate } from './api.js'
+import { CryptoAdapter } from './crypto-adapter.js'
 
 export interface RondevuOptions {
     apiUrl: string
     username?: string  // Optional, will generate anonymous if not provided
     keypair?: Keypair  // Optional, will generate if not provided
+    cryptoAdapter?: CryptoAdapter  // Optional, defaults to WebCryptoAdapter
 }
 
 export interface PublishServiceOptions {
@@ -52,11 +54,13 @@ export class Rondevu {
     private username: string
     private keypair: Keypair | null = null
     private usernameClaimed = false
+    private cryptoAdapter?: CryptoAdapter
 
     constructor(options: RondevuOptions) {
         this.apiUrl = options.apiUrl
         this.username = options.username || this.generateAnonymousUsername()
         this.keypair = options.keypair || null
+        this.cryptoAdapter = options.cryptoAdapter
 
         console.log('[Rondevu] Constructor called:', {
             username: this.username,
@@ -89,14 +93,14 @@ export class Rondevu {
         // Generate keypair if not provided
         if (!this.keypair) {
             console.log('[Rondevu] Generating new keypair...')
-            this.keypair = await RondevuAPI.generateKeypair()
+            this.keypair = await RondevuAPI.generateKeypair(this.cryptoAdapter)
             console.log('[Rondevu] Generated keypair, publicKey:', this.keypair.publicKey)
         } else {
             console.log('[Rondevu] Using existing keypair, publicKey:', this.keypair.publicKey)
         }
 
-        // Create API instance with username and keypair
-        this.api = new RondevuAPI(this.apiUrl, this.username, this.keypair)
+        // Create API instance with username, keypair, and crypto adapter
+        this.api = new RondevuAPI(this.apiUrl, this.username, this.keypair, this.cryptoAdapter)
         console.log('[Rondevu] Created API instance with username:', this.username)
     }
 

src/web-crypto-adapter.ts

@@ -0,0 +1,67 @@
+/**
+ * Web Crypto adapter for browser environments
+ */
+
+import * as ed25519 from '@noble/ed25519'
+import { CryptoAdapter, Keypair } from './crypto-adapter.js'
+
+// Set SHA-512 hash function for ed25519 (required in @noble/ed25519 v3+)
+ed25519.hashes.sha512Async = async (message: Uint8Array) => {
+    return new Uint8Array(await crypto.subtle.digest('SHA-512', message as BufferSource))
+}
+
+/**
+ * Web Crypto implementation using browser APIs
+ * Uses btoa/atob for base64 encoding and crypto.getRandomValues for random bytes
+ */
+export class WebCryptoAdapter implements CryptoAdapter {
+    async generateKeypair(): Promise<Keypair> {
+        const privateKey = ed25519.utils.randomSecretKey()
+        const publicKey = await ed25519.getPublicKeyAsync(privateKey)
+
+        return {
+            publicKey: this.bytesToBase64(publicKey),
+            privateKey: this.bytesToBase64(privateKey),
+        }
+    }
+
+    async signMessage(message: string, privateKeyBase64: string): Promise<string> {
+        const privateKey = this.base64ToBytes(privateKeyBase64)
+        const encoder = new TextEncoder()
+        const messageBytes = encoder.encode(message)
+        const signature = await ed25519.signAsync(messageBytes, privateKey)
+
+        return this.bytesToBase64(signature)
+    }
+
+    async verifySignature(
+        message: string,
+        signatureBase64: string,
+        publicKeyBase64: string
+    ): Promise<boolean> {
+        try {
+            const signature = this.base64ToBytes(signatureBase64)
+            const publicKey = this.base64ToBytes(publicKeyBase64)
+            const encoder = new TextEncoder()
+            const messageBytes = encoder.encode(message)
+
+            return await ed25519.verifyAsync(signature, messageBytes, publicKey)
+        } catch {
+            return false
+        }
+    }
+
+    bytesToBase64(bytes: Uint8Array): string {
+        const binString = Array.from(bytes, byte => String.fromCodePoint(byte)).join('')
+        return btoa(binString)
+    }
+
+    base64ToBytes(base64: string): Uint8Array {
+        const binString = atob(base64)
+        return Uint8Array.from(binString, char => char.codePointAt(0)!)
+    }
+
+    randomBytes(length: number): Uint8Array {
+        return crypto.getRandomValues(new Uint8Array(length))
+    }
+}