Simple "Time-based One-Time Password" generator without dependency (except jvm)
I wrote this program to have a unique class that I can deploy quickly and where I want. You just need a java 1.8 vm or higher and your base 32 secret (from google / vip access / ...).
Usage:
The program takes your secret as a parameter and generates an OPT. It displays it, gives the remaining validity (2 seconds in advance), copy it to the clipboard and waits 8 seconds before stopping. WARNING: in case you use linux, the content of the clipboard is no longer available after the program has stopped (hence the delay of 8s).
Note:
I thank Gray Watson for his lib. (https://github.com/j256/java-two-factor-auth)
I start form his otp generation method and I rewrote the parsing of the secret (b32 to ByteArray) to have a shorter (but probably less generic) solution integrated in a single java file with less than 150 lines.