Kertakäyttösalasanan

Kertakäyttösalasana, or one-time password (OTP), is a password that is valid for only one login session or transaction. It is a security feature used to provide an additional layer of authentication. Unlike traditional passwords, which remain the same until changed, kertakäyttösalasanat are dynamically generated and expire after a short period or upon successful use.

The generation of kertakäyttösalasanat typically relies on time-based or event-based algorithms. Time-based one-time passwords (TOTP) are the most common, synchronized between a server and a user's device (like a smartphone app or hardware token) based on a shared secret and a continuously changing time code. Event-based one-time passwords (HOTP) are generated based on a counter that increments with each new password.

Kertakäyttösalasanat are often used in multi-factor authentication (MFA) systems. After a user enters their primary password, they are prompted for a kertakäyttösalasana to verify their identity. This significantly enhances security by making it much harder for unauthorized individuals to gain access even if they have compromised the user's primary password. Common applications include online banking, secure remote access, and sensitive account management. The use of kertakäyttösalasanat helps mitigate risks associated with password reuse, phishing, and credential stuffing attacks.