FreeOTP

NOTE: Users reported issues with the backup & restore functionality, please test this whenever you install the app on a new device.

FreeOTP is a two-factor authentication (2FA) application for systems utilizing
one-time password protocols (OTP). Tokens can be added easily by scanning a
QR-code or by manually entering in the token configuration.

FreeOTP implements open standards. This means that no proprietary server-side
component is necessary: use any server-side component that implements these
standards - for example FreeIPA, which uses TOTP. Any
standards-compliant implementation will work. Currently, FreeOTP provides
implementations of HOTP (RFC 4226) and TOTP (RFC 6238).