Pretty much, they're usually based on shared secrets and the current time. Check out https://en.wikipedia.org/wiki/Time-based_one-time_password https://en.wiki

Pretty much, they're usually based on shared secrets and the current time. Check out https://en.wikipedia.org/wiki/Time-based_one-time_password https://en.wikipedia.org/wiki/Time-based_one-time_password and https://en.wikipedia.org/wiki/HMAC-based_one-time_password https://en.wikipedia.org/wiki/HMAC-based_one-time_password for some of the finer details