In today's rapidly evolving digital landscape, where data breaches and cyber threats have become more prevalent than ever, safeguarding our online presence is of paramount importance. Traditional username-password authentication methods alone can no longer guarantee the level of security needed to protect sensitive information. Enter one-time passwords (OTPs), a powerful and dynamic security mechanism designed to fortify our digital defenses.

In an era where multi-factor authentication (MFA) has become a standard practice, OTPs have emerged as a vital component of this layered security approach. Unlike static passwords that can be easily compromised or reused, one-time passwords provide an additional layer of protection by introducing a time-limited, unique code for each login attempt. By doing so, OTPs significantly reduce the risk of unauthorized access and elevate the security posture of both individuals and organizations.

There are 2 most popular OTP technologies: HOTP and its successor TOTP. They are documented using RFCs.