Einmalpasswort

EinmalPasswort, often abbreviated as OTP, is a password that is valid for only one login session or transaction. It is a security measure used to protect against replay attacks, where an attacker intercepts a password and reuses it to gain unauthorized access. OTPs are typically generated dynamically and are unique for each use.

There are several common methods for generating and delivering OTPs. Time-based one-time passwords (TOTP) are generated using a shared secret key and the current time. These are often used in two-factor authentication (2FA) systems, where a user enters their regular password and then an OTP generated by an authenticator app or a hardware token. Event-based one-time passwords (HOTP) are generated based on a counter that increments with each use.

Another method involves sending OTPs via SMS or email. While convenient, these methods are considered less secure than TOTP or HOTP due to the potential for interception of messages or compromise of email accounts. OTPs are a crucial component in modern cybersecurity strategies, enhancing the security of online accounts and sensitive transactions. They help mitigate risks associated with static passwords, which can be stolen or brute-forced. The implementation of OTPs is a widely adopted practice by financial institutions, online services, and government agencies to safeguard user data and prevent fraud.