YAS-web

Encrypted-key storage playground. RSA key pairs are generated in the browser, the private key is wrapped with a passphrase-derived AES-GCM key, and only ciphertext plus KDF metadata ever reach the server. A JWT-protected API lets you sync the encrypted blob to MongoDB while keeping the passphrase local.

Architecture

• Backend: Express + TypeScript + MongoDB (Mongoose). /api/auth handles signup/login and issues JWTs; /api/accounts stores and fetches encrypted key material. Account writes are guarded by Authorization: Bearer <token>.
• Frontend: React + Vite + TypeScript. Generates RSA-4096 pairs, derives AES-GCM keys via PBKDF2 (310k iterations) and can be extended to scrypt/Argon2. Includes a tabbed UI for managing keys, copying the public key, and handling future encrypt/decrypt UX.
• Data shape: { username, publicKey, encryptedPrivateKey: { cipherText, iv, authTag? }, kdf: { algorithm, salt, keyLength, iterations?, memoryCost?, parallelism?, hash? }, notes, timestamps }. Passphrases and plaintext keys never leave the browser.

Quick start

Prereqs: Node 18+, pnpm/npm/yarn, and MongoDB running locally (default URI mongodb://localhost:27017/yas-web).

Backend

1. cd backend
2. cp .env.example .env and set MONGODB_URI, JWT_SECRET, CORS_ORIGIN
3. npm install
4. npm run dev (listens on http://localhost:4000)

Frontend

1. cd frontend
2. cp .env.example .env (configure VITE_API_BASE if you change the backend origin)
3. npm install
4. npm run dev (Vite on http://localhost:5173)

Environment variables

• backend/.env
  • MONGODB_URI – Mongo connection string
  • PORT – API port (default 4000)
  • JWT_SECRET – signing key for auth tokens (required in prod)
  • CORS_ORIGIN – frontend origin allowed by CORS (default *)
• frontend/.env
  • VITE_API_BASE – base URL for API requests (default http://localhost:4000/api)

API

Auth

• POST /api/auth/signup

  { "username": "alice", "password": "StrongP@ssw0rd" }

  Creates the user after strength validation (>=10 chars, upper/lower/number/symbol).

• POST /api/auth/login

  { "username": "alice", "password": "StrongP@ssw0rd" }

  Returns { "token": "<jwt>", "user": { "id", "username" } }. Use the token as a Bearer auth header for account writes.

Accounts

• POST /api/accounts (requires Authorization: Bearer <jwt>)

  {
    "username": "alice",
    "publicKey": "-----BEGIN PUBLIC KEY-----...",
    "encryptedPrivateKey": {
      "cipherText": "base64",
      "iv": "base64",
      "authTag": "base64" // optional, AES-GCM tag (browser crypto stacks it onto cipherText)
    },
    "kdf": {
      "algorithm": "PBKDF2",
      "salt": "base64",
      "iterations": 310000,
      "keyLength": 32,
      "hash": "SHA-256"
    },
    "notes": "optional text"
  }

  Upserts by username. Returns { id, createdAt, updatedAt, upserted } with 201 Created for first write and 200 OK for updates.

• GET /api/accounts/username/:username

• GET /api/accounts/:id

Both read endpoints return the sanitized record (public key + encrypted blob + metadata). Private material stays encrypted.

Security notes

• Passphrases stay in the browser; only ciphertext, IV, optional authTag, KDF metadata, username, public key, notes, and timestamps are persisted.
• JWT secret falls back to dev-secret only when unset; set a strong JWT_SECRET before deploying.
• Consider rate limiting, Argon2/scrypt KDF options, and hardware-backed key storage for production setups.

Next steps

• Ship the encrypt/decrypt tabs to support hybrid file sharing (AES payload + RSA-OAEP wrapped key).
• Offer user-selectable KDFs (PBKDF2, scrypt, Argon2) with UI guidance on memory/CPU tradeoffs.