One time passwords (OTP) is an automatically generated numeric or alphanumeric string of characters that authenticates entities for a single login session. And it is a password that expires quickly and cannot be reused. That means, after users log in to a system, the password will be no longer valid and cannot be used for future login attempts. It is a collection of numbers and/or characters generated and sent to entities to be used only for a single login purpose. Moreover, it commonly applied as part of a multifactor authentication (MFA) procedures.
The main difference between the traditional password and one time password (OTP) is that OTP is used once and will not work if reused to gain access. Besides, it can be used either in hard tokens or software based tokens.
There are mainly two types of one time passwords (OTP), namely:
- Time-based OTP (TOTP): This type of OTP provides time frame within which the password or the OTP code will be valid, usually 30-60 seconds in length.
- Hash-based OTP (HOTP): This type of OTP generates and send a hash value to the entity attempting to gain access.
Some benefits of one time passwords (OTP) include the following:
- Difficult to guess
- Prevent replay attacks
- Reduces risks of compromise of password
- Prevent online identity theft
- Minimizes password security issues
- Reduce support from IT team
- Easy password management