0
votes
2answers
57 views

Are there any flaws in my design for a paper-based OTP grid?

I'm trying to implement two-factor authentication on the cheap for a website of mine. My bank uses this sort of grid-based OTP system, so I wanted to emulate it in my application: Cards are ...
1
vote
2answers
459 views

How to write a rock solid TOTP implementation?

I am currently writing a TOTP implementation in PHP (but this applies to other languages as well) and of course want it to be as secure as possible, what should be considered? After reading the ...
0
votes
2answers
821 views

Google Authenticator - Counter Based [duplicate]

I'm trying to understand How google authenticator - counter based work. I have tried googling around finding a demo or at least how this work. I understand its a one time password but not like TOTP. I ...