Google Authenticator

A small D library to generate the google authenticator code.

inspired from https://github.com/tilaklodha/google-authenticator

• Install a D Language compiler https://dlang.org/
• Install Dub package manager
  • On OSX run brew install dub.
  • On Ubuntu snap install --classic dub
  • Follow instructions on https://code.dlang.org/ for other OSes.

The OTP auth code works on the secret token and the current time.

The time on your local machine should be in sync according to NTP.

The secret token usually is given to the user on the first configuration as a base32-encoded string or acquired via QR code.

The library exposes two functions:

• getHOTPToken given a "secret" and a time interval, returns the 6-digit HOTP Token as a string
• getTOTPToken given a "secret", returns the 6-digit TOTP Token as a string using the current time

more details on the algorithm on https://en.wikipedia.org/wiki/HMAC-based_One-time_Password_algorithm

usage:

1. add the library as a dependency in your dub project:

$ dub add gauthenticator

2. use the library by calling getTOTPToken() or getHOTPToken() functions

import std.stdio;
import gauthenticator;

void main()
{
	writeln(getTOTPToken("foobarbaz"));
}