My understanding is that for PAKE protocols such as OPAQUE (https://eprint.iacr.org/2018/163.pdf), the the adversary has no choice but to just do online attacks on the password. If this is true, I have 2 questions (which hopefully can be answered with references to RFC, NIST, etc.):

  1. What is a reasonable entropy level of the password so that is it practically immune to online dictionary attacks?
  2. What are good password requirements to enforce this minimum entropy level?


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    $\begingroup$ It would be difficult to give an answer to this without asking "how many on-line queries can an attacker perform?" The answer to this depends on the application (how much rate limitation do they do on a failed login request?) $\endgroup$
    – poncho
    Jun 15, 2022 at 17:22
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    $\begingroup$ I agree. I don't know typical parameter for this. Is it possible to give a somewhat generic answer? E.g. with N on-line guesses rate limit? $\endgroup$
    – Joe
    Jun 15, 2022 at 17:48


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