Security

Non‑custodial

• Never store plaintext private keys; the server does not hold keys.

• All signatures are performed on the user’s device.

Local Protection

• KDF: Argon2id (PIN) → B

• Encryption: AES‑GCM (random IV)

• Lock (local secret): Sensitive materials are encrypted as a separate blob and unlocked when needed.

Backup / Restore

• Only an encrypted bundle is stored in Google Drive (AppData).

• On a new device, users can recover with their PIN (self‑recovery).