EinmalPasswortAuthentifizierung

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 provide additional protection beyond a traditional static password. OTPs are typically generated dynamically and are time-sensitive or transaction-specific.

There are several common methods for generating and delivering OTPs. One method is through a hardware token, a small device that generates a new code at regular intervals, usually every 30 or 60 seconds. Another common method is through software tokens, which can be applications on a smartphone or computer that generate OTPs. These are often synchronized with a server using an algorithm like Time-based One-Time Password (TOTP) or HMAC-based One-Time Password (HOTP). SMS-based OTPs are also widely used, where a code is sent via text message to a registered mobile number.

OTP systems are frequently implemented as part of a two-factor authentication (2FA) or multi-factor authentication (MFA) strategy. In such systems, a user must provide two or more distinct pieces of evidence to verify their identity. This typically involves something the user knows (like a password) and something the user has (like a phone or hardware token that generates the OTP). The use of OTPs significantly enhances security by making it much harder for unauthorized individuals to gain access, even if they manage to obtain the user's static password.