The following is a general comparison of OTP applications that are used to generate one-time passwords for two-factor authentication (2FA) systems using the time-based one-time password (TOTP), the HMAC-based one-time password (HOTP) algorithms or Mobile-OTP (mOTP), which is an older, open source, 2FA system for mobile phones that combines a user’s PIN, time and a per-device secret to generate OTPs. It also lists apps that support proprietary authentication methods, like those used by Steam or Yandex.