Google Authenticator TOT vs HOTP: Understanding the Difference

Two-Factor Authentication (2FA) has become increasingly popular in recent years, and for good reason. It adds an extra layer of security to your online accounts by requiring a unique code, in addition to your password, to access your account. One of the most common 2FA methods is using an authenticator app like Google Authenticator, which generates codes based on Time-Based One-Time Password (TOTP) or HMAC-based One-Time Password (HOTP) algorithms.

TOTP vs HOTP: What's the Difference?

When setting up a 2FA account manually with Google Authenticator, you have the option to choose between TOTP and HOTP algorithms. The main difference between these two algorithms lies in how they generate codes.

TOTP uses a time-based algorithm that generates codes based on the current time. This means that every 30 seconds, you'll receive a new code that is valid for the next 30 seconds. If you don't use the code within this timeframe, it will expire and become invalid.

HOTP, on the other hand, uses a counter-based algorithm that combines a secret key or seed with a counter to generate codes. The counter is incremented each time a code is generated, and the same code cannot be reused.

How Do I Set Up My Authenticator Accounts Manually?

Setting up your authenticator accounts manually with Google Authenticator is relatively straightforward. First, you'll need to enter your 2FA secret key or seed, which is provided by your service provider. You can also set up your account by scanning a QR code.

Once you've entered your secret key or scanned the QR code, you'll be prompted to choose between TOTP and HOTP algorithms. The default setting for most accounts is TOTP, but if your service provider requires special settings, you can change the parameters such as period, time, and algorithm.

How Does Google Authenticator Work?

Google Authenticator generates codes instantly, even without an internet connection. This means that you'll always have access to your 2FA codes, wherever you are and whenever you need them.

To use the authenticator app, simply download and install it on your preferred device, and then set up your account manually or automatically by scanning a QR code from any service or app that offers 2FA codes. Google Authenticator is available for iOS, Android, and Desktop (Windows, Mac, and Linux).

What Are HOTPs?

HOTPs are generated using a cryptographic hash function, which combines a secret key or seed with a counter to produce a unique code. This code is then shortened to a six or eight-digit OTP.

At the heart of HOTP is a secret key, which is only known by the user's token and the server that validates submitted OTP codes. The counter on the token is generated when the button is pressed, while the counter on the server is incremented only when an OTP is successfully validated.

In conclusion, Google Authenticator offers two algorithms for generating 2FA codes: TOTP and HOTP. While both algorithms are secure, they work in different ways and have different characteristics. By understanding the difference between these two algorithms, you can make informed decisions about how to set up your authenticator accounts manually with Google Authenticator.

Google authenticator totp vs hotp