Why does my OTP code change regularly?

A One-Time Password (OTP) code changes regularly, primarily for security reasons. Here’s why:

Why Does an OTP Code Change?#

Single Use#

An OTP can only be used once. Once it is used or after a certain period (often 30 to 60 seconds), it becomes invalid, and a new code is generated. This prevents any fraudulent reuse, even if the code is intercepted by a malicious third party.

Time Limitation#

Time-based OTPs (TOTP) automatically change every 30 to 60 seconds, while event-based OTPs (HOTP) change after each use. This rapid rotation significantly reduces the window of opportunity for attacks.

Protection Against Replay Attacks#

Even if an attacker manages to intercept an OTP, they will not be able to use it a second time, as the code will have already expired or changed.

Advantages of This Method#

Enhanced Security#

OTP adds an extra layer of security, especially when used as part of two-factor authentication (2FA). Even if a main password is compromised, the absence of the OTP code prevents unauthorized access.

Reduced Risk of Hacking#

The very short lifespan and uniqueness of the code make brute force or phishing attacks much less effective.

Protection Against Reuse#

Unlike static passwords, an OTP cannot be reused, which limits the risks associated with compromised credentials.