What is 2FA and why 2FA?🤔

2FA stands for two factor authentication. It adds an extra layer of security other than password. The user must enter a 2FA code along with password in order to sign in. 2FA codes can be generated in two ways, time based codes and counter based codes.

Advantages of 2FA over E-Mail or SMS verification:

• No network required: 2FA codes can be generated offline.
• 🛡️ Better security.

Time based codes vs counter based code.

| Time based codes | Counter based codes | | :--------------------------------------------------- | :----------------------------------------------------------- | | Time based codes changes depending on time. 🕖 | Counter based codes change depending on number of successful sign-in(s). ✔️ | | No need of adding counter every time in client side. | After every successful login, counter must be increased by one in server side as well as client side. |

2FA with Python

Requirements

• onetimepass python package (Can be installed using the command: pip install onetimepass).
• Your favourite authenticator app (Example: Google authenticator, Microsoft authenticator).

Let's start!👀

For both time based codes and counter based code, a secret string is securely shared with the authenticator app while setting up 2FA. All codes are generated based on this secret string. This string is not case sensitive.

🕖Time based codes

Let us now, write a simple Python script to understand how time based 2FA works!

✔️ Counter based codes

Here is a complete Python script to understand how counter based 2FA works!

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