@curbapps/crypto

Auditable end-to-end encryption for CurbApps. This package is the only place client code should derive keys, wrap keys, or encrypt user data.

The implementation is TypeScript on @noble/hashes, @noble/ciphers, @noble/curves, and WebCrypto AES-GCM when crypto.subtle is available. There is no WASM blob and no server-side decrypt path.

Algorithms

• Argon2id (OWASP floor: 19 MiB, t=2, p=1) derives a master key from a password
• AES-KW-256 wraps the random Account Encryption Key (AEK)
• AES-256-GCM encrypts entity payloads (protocol v1)
• XChaCha20-Poly1305 encrypts chunked attachments (protocol v2)
• X25519 ECDH wraps keys for another device or account
• Ed25519 signs identity public keys so the sync server cannot inject a peer key

Read SPEC.md for envelopes, the key hierarchy, and test vectors. Read threat-model.md for what a stolen server or stolen browser profile can and cannot do.

Install

pnpm add @curbapps/crypto

In the CurbApps monorepo this directory is a git submodule. Clone with:

git clone --recurse-submodules https://github.com/CurbSoftware/curbapps-monorepo.git

What this package does not do

• It does not talk to the network.
• It does not persist keys. Hosts use SecureAekStore for auto-unlock.
• It does not implement billing, apps, or UI.
• Auto-unlock in a browser extension is as strong as browser.storage.local. A master password is required for cloud recovery.

Develop

pnpm install
pnpm test
pnpm typecheck
pnpm lint

Python verifier (optional, for published vectors):

python3 -m pip install -r verify/requirements.txt
python3 verify/verify.py