E2E Encryption — Testing

Test strategy

Encryption tests verify cryptographic correctness of key generation, message encryption/decryption, key wrapping, and transport-layer encryption. These are primarily unit tests on the crypto service layer and do not require a running server.

---

Unit tests — crypto services

Key generation (peer-key-service.ts)

Scenario	Expected result
Generate key pair	Returns { publicKey: Uint8Array(32), secretKey: Uint8Array(32) }
Two calls produce different key pairs	Public keys are not equal
Public key length	Exactly 32 bytes (Curve25519)

Key derivation (key-derivation.ts)

Scenario	Expected result
Same password + same salt → same DeviceKey	Keys are equal
Different password → different DeviceKey	Keys are not equal
Different salt → different DeviceKey	Keys are not equal

Key wrapping / unwrapping (local-encryption-service.ts)

Scenario	Expected result
Wrap private key with DeviceKey	Returns ciphertext + nonce
Unwrap with same DeviceKey	Returns original private key
Unwrap with wrong DeviceKey	Returns null or throws
Wrapped blob differs from plaintext key	wrappedKey !== secretKey

Message encryption (tcp-encryption.ts, ws-encryption.ts)

Scenario	Expected result
Encrypt with Alice's private + Bob's public	Ciphertext ≠ plaintext
Decrypt with Bob's private + Alice's public	Returns original plaintext
Decrypt with wrong key pair	Returns null
Same plaintext encrypted twice	Different ciphertexts (random nonce)
Tampered ciphertext	Decryption returns null

---

Integration tests — key registration and lookup

Scenario	Expected result
POST /keys/register with valid public key	200, signed_credential returned
GET /keys/<peer_id> after registration	200, returns registered public key
GET /keys/<peer_id> for unknown peer	404 Not Found
SERVER_ED25519_SEED set	signed_credential is a valid Ed25519 signature
SERVER_ED25519_SEED unset	signed_credential is null or absent

---

Key recovery round-trip tests

Scenario	Expected result
Wrap WrappedKey under recovery credential	Produces distinct ciphertext
Unwrap with correct recovery credential	Returns original WrappedKey
Unwrap with wrong recovery credential	Returns null
Full round-trip: wrap → store → retrieve → unwrap	Original private key recovered

---

Coverage targets

• Key generation: 100% branch coverage.
• Encrypt/decrypt: happy path, wrong key, tampered ciphertext — all branches covered.
• Key derivation: same-input determinism and different-input divergence verified.
• No test may log or assert on real private key material.

---

Test conventions

• Use tweetnacl.box.keyPair() to generate synthetic key pairs in tests.
• Mock expo-secure-store — do not write to the device keystore in unit tests.
• Reset peer_key and wrapped_key tables between integration test runs.