An OTP is an automatically generated and secure numeric or alphanumeric string of characters that authenticates a user for a single transaction or login session.
Unlike the usual run of the mill passwords you use to log in to a site or app, an OTP (One Time Passcode) is valid for one use only. They are sent to previously provided details such as a phone number or email address. They typically expire after a short duration. Something like 1 to 5 minutes is typical, but some can be 10 minutes. It serves as a second layer of defence in Two Factor Authentication (2FA) and Multi Factor Authentication (MFA). They can also come from authentication apps or be physical hardware tokens.
