Blog / Authentication / OTP, TOTP, HOTP: What is the Difference?
OTP, TOTP, HOTP: What is the Difference?
28 Feb 2022

Whenever you sign up on some social platform, banking application, or even some game you get a message to enable 2FA. If you enable this, you will always get a one-time password on mobile via SMS or email. This is needed to make things secure by adding a layer of security. 2FA means Two Factor Authentication and one factor is the password you set while the other is a one-time password.

These days there are so many security issues that there are different kinds of this One-time password known as OTP, TOTP, and HOTP. So, here we will discuss everything about them so you can know the difference between them.

What is OTP?

Simple OTP means a one-time password that is usually an alphanumeric code sent for authentication. This code is randomly generated by the server and lasts for single usage only. As it is used for once, the code automatically expires, and you need the new one to authenticate yourself

Pros of OTP:

·         Very convenient to use

·         The user gets peace of mind that stolen passwords are also safe

·         Better security than only using passwords

Cons of OTP:

·         Getting out of sync is a common problem

·         Not receiving this code can log you out of your account

·         Not that cheap to integrate

What is TOTP?

TOTP means Time based one-time password. While the name is pretty much explanatory, this is also an OTP, but it only works for a specific time. The code here is also generated by the server randomly and it contains different characters with varying lengths sometimes.

The interesting fact is that this code is only valid for a specific time limit which is usually set between 30 and 180 seconds but this time limit can be changed as well.

Pros of OTP:

·         Very inexpensive to implement get highly functional

·         The process of code generation is not that heavy

·         TOTP technology remembers users and locks account after several wrong attempts

Cons of OTP:

·         Not having a device will keep you from even making the smallest transactions

·         The secret key can be cloned, and it will generate valid codes, so this is not that secure

·         Users may find it inconvenient if the code is too long or their mobile device does not auto-fill it.

What is HOTP?

To take security to the next level, HOTP is used. HOTP is also known as Hash-based one-time password or HMAC based one-time password which also means hash message authentication code one-time password.

The interesting thing here is that its generation is event-triggered, and it can only be known by the user and server. The reason for that is that it is founded on hash algorithms so nobody else can get this code. As it is based on hash, it is called HOTP.

Pros of OTP:

·         These passwords are more user friendly as a hash algorithm is doing everything

·         These are not limited by any timestamp or other usage criteria

·         Most secure among OTP, TOTP, and HOTP.

Cons of OTP:

·         This is also dependent on external factors like SMS or the internet for emails.

·         Getting failed login with unusable tokens can be a problem if there is a lag in the system

·         If the hacker cracks the algorithm that is generating codes for you then your security is in danger.

What are the fields that need these one-time passwords?

With everything going online it has become highly important for all the online and digital platforms to be secured with OTP, TOTP, and HOTP. Some fields of life whose security is only based on these passwords are:

·         Internet companies like Google and social media platforms

·         Ecommerce and Finance

·         Government organizations

·         Cryptocurrency trading platforms

·         E-Games which include in-app purchases and more

As a One-time password is mostly sent to your mobile number, this acts as a physical factor that is always under your possession. So, things become extremely efficient in providing better security.


As most of our lives today rely on the online world, it is very important to make things secure. The digital world cannot be secured with physical surveillance and locks, so passwords are used as locks. However, modern-day hackers even get through that.

So, there is a need for an even more secure option which is provided by OTP, TOTP, and HOTP. Each of these come with their distinct features and they have become necessary for most digital and online platforms.

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