For educational purposes, I implemented every algorithm in Java! I meant to make a book out of that, but who still reads books? If you find any issues, please fork the repository and send me a pull ...
* Generates a Time-based One-time Password (TOTP) using HMAC-SHA1. * The secret key is provided as a hexadecimal string. * Time steps are in seconds. Digits specifies the length of the OTP.