@clasp-to/crypto

E2E encryption add-on for CLASP protocol clients. Provides client-side AES-256-GCM encryption that is transparent to the router.

Install

npm install @clasp-to/crypto

Peer dependency: @clasp-to/core ^4.0.0

Quick Start

import { Clasp } from '@clasp-to/core'
import { CryptoClient, MemoryKeyStore } from '@clasp-to/crypto'

const clasp = new Clasp('ws://localhost:7330')
const crypto = new CryptoClient(clasp, {
  identityId: 'device-1',
  store: new MemoryKeyStore(),
})

// Create an encrypted session
const session = crypto.session('/myapp/signals', {
  rotationInterval: 3_600_000, // 1 hour
})
await session.start()
await session.enableEncryption()

// Encrypted set/emit -- CryptoClient handles encryption automatically
await crypto.set('/myapp/signals/fader', 0.75)
await crypto.emit('/myapp/signals/trigger', { note: 60 })

// Encrypted subscribe -- auto-decrypts E2E envelopes
crypto.subscribe('/myapp/signals/**', (data, address) => {
  console.log(address, data) // decrypted automatically
})

API

CryptoClient

Wraps a Clasp instance for transparent encrypt/decrypt.

• session(basePath, options?) -- get or create an E2ESession
• set(address, value) -- encrypts if a session matches, otherwise passes through
• emit(address, payload?) -- same behavior as set()
• subscribe(pattern, callback) -- auto-decrypts E2E envelopes before callback
• close() -- destroys all sessions

E2ESession

Manages key exchange and encryption for one group/room/channel.

• start() -- subscribe to key exchange paths, load persisted key
• enableEncryption() -- generate a new group key
• requestGroupKey() -- request the group key from peers
• encrypt(value) -- encrypt a string into an E2EEnvelope
• decrypt(envelope) -- decrypt an E2EEnvelope back to a string
• rotateKey() -- generate a new key and distribute to peers
• destroy() -- clean up subscriptions and zero key material

Storage Backends

• MemoryKeyStore -- in-memory, for testing or ephemeral sessions
• IndexedDBKeyStore -- browser-based persistent storage

Documentation

See the E2E Encryption Guide for the full protocol description, key exchange flow, and security properties.

License

MIT