LuTiao Programming

Nov 2, 2026 · Backend Development

Complete Java TOTP 2FA Implementation: QR Binding, Replay Protection & Recovery Codes

This article details a production-ready Java implementation of TOTP two-factor authentication covering QR code binding, secret encryption, time-drift handling, replay attack prevention via atomic step consumption, rate limiting, recovery codes with hashed storage, and secure 2FA disable flows requiring re-authentication.