A One-Time PIN (OTP) is a temporary numerical code, typically composed of a string of digits, generated and sent to a user's mobile phone or email address for a specific authentication or authorization event. OTPs are widely used to enhance security by providing a unique and time-sensitive method to validate the identity of a user during online transactions, login processes, or account access.

Key aspects and functionalities of One-Time PINs include:

Temporary and Unique: OTPs are valid for a short duration and can only be used once for the intended purpose, adding an extra layer of security.

Authentication Mechanism: OTPs serve as an effective method for verifying the identity of users, especially during login attempts, transaction confirmations, or sensitive account access.

Delivery Channels: OTPs can be delivered to users through various channels, including SMS, email, mobile apps, or hardware tokens, depending on the implementation and security requirements.

Two-Factor Authentication (2FA): OTPs are commonly used as one of the factors in two-factor authentication, where users need to provide something they know (password) and something they have (OTP) for secure access.

One-Time PINs play a crucial role in enhancing digital security and protecting users from unauthorized access or fraudulent activities. They are widely adopted in online banking, e-commerce, email verification, and other applications requiring secure user authentication.