I need a self-custody USDT wallet built as a mobile app that runs smoothly on both iOS and Android. Absolute ownership of the keys stays on-device; nothing is ever parked on a server. Two-factor authentication must protect every sensitive action—wallet creation, recovery, transfers, and settings—so the flow has to integrate native push or TOTP seamlessly. The interface can stay lean: create or import a wallet, show balances for TRC-20 and ERC-20 USDT, generate and scan QR codes, let the user pick gas or fee levels, then surface a clear transaction history. Under the hood, please rely on well-maintained open-source libraries for key generation, secure enclave / keystore storage, and AES-encrypted local backups. Builds should compile with the latest Xcode and Android Studio toolchains and be ready for App Store and Play Store security checks. Acceptance criteria • Test IPA and APK that demonstrate a complete send / receive flow protected by 2FA • Full source code with reproducible build instructions • Short security report outlining how keys, secrets, and 2FA data are handled • One hand-off call to walk me through building from scratch If you can optionally layer in biometric unlock or end-to-end encrypted cloud backups, flag that in your bid, but the scope above is the baseline. Looking forward to collaborating on a rock-solid, secure wallet.