How is synchronization of counter values achieved in the HOTP protocol? As I understand it, the server increments its counter value only if a match (of the OTP value) is found. What happens at ...
From RFC 4226 I understand how HOTP generates one-time passwords by incrementing a counter and uses the 'look-ahead' window to try to resynchronise (from this counter), if the user tries a few wrong ...
My understanding of HOTP is that each password is unique and based on a counter. $$PASSWORD = HOTP_1(K,C)$$ Where $C$ is an incremental counter. What I wish to know, is how you keep the client ...