4 ms·

Problem with generators and this scheme, they allow regeneration. Most people not using the first version, they generate a new until they like it enough to stop

by mlaci 6y ago

Problem with generators and this scheme, they allow regeneration. Most people not using the first version, they generate a new until they like it enough to stop, which is not that random anymore as they think.

pkhamre 6y ago
So you're saying that generating a new password looses entropy?
- setr 6y ago
  Choosing is the problem here -- it's now only as random as your preference Eg the scheme doesn't do its job well if you don't know the word, so the dictionary can be reduced by that much
  - ResidentSleeper 6y ago
    On the other hand, I'd wager that the set of words that you can recognize is vastly larger than the set of words that you're likely to come up with on the spot. Hence, using a generator would still result in higher entropy then trying to come up with a password yourself. Random numbers picked by humans are notoriously biased. I'm guessing it's even worse when you ask them to come up with random words.
- mlaci 6y ago
  Yes, if the regeneration depends on your preference of the generated words, the words order or link between them. The individual generations independent from each other, so if your choice – how many regeneration you do - not depends on the generations outcome, for example on your birthday date or favorite number, their randomness are equal. But randomness are not enough, it's possible the first generated version correlate with your preference and that situation does not really matter why are you stopped generating new password. Predictability of this scheme very good, because the strict rules. All implementation using common english words. For words smaller length, easy spelling, less ambiguity are preferred. Mixing nouns verbs and adjectives are more meaningful, order also adds more meaning. Word count very limited. Preference on the separator character also very rigid. Personal preference more known, because hidding your preference on all english words very hard and mostly unconscious.
mlyle 6y ago
A mild amount of regeneration doesn't hurt, though. If you generate 4 and pick your favorite, you've shaved less than 2 bits of entropy off.
- mlaci 6y ago
  It's just a bare minimum that you reduced, if you add some preference it's worse than that. I did some test, maybe I'm just lucky, but i got password with a word starting with b at the 3rd generation, and i got adjective-noun pair in that order at the 5th generation.
  - mlyle 6y ago
    > It's just a bare minimum that you reduced No, it's the -maximum- that I reduced entropy by. If I choose randomly from 4 possible passwords, I've shaved off --no entropy--. If I choose with a strongly predictable preference (say, everyone knows I'll pick the password that's first alphabetically) I've shaved nearly 2 bits off the probable search space: you probably only need to look in the first 1/4th of the search space. Choosing with some subtle, individual preferences is something inbetween.
    - mlaci 6y ago
      > with a strongly predictable preference No, your example has nothing to do with preference, your method (picking out of 4) just less random than picking from one (the first). Preference is, when certain passwords more likely to be picked than others or at those passwords less likely to be stepped over to generating a new one. Wtih strong preference you regenerate until you got that preferred password, for example you prefer short words and the attacker know that, at first trying combinations with short words has better chance to cracking the password.
      - mlyle 6y ago
        You're just talking past me, bro. Regenerating and picking your favorite from a few is reasonable and isn't a big entropy penalty (the penalty is easily bounded). Infinitely re-rolling until you get the exact phrase "correct horse battery staple" obviously has a severe entropy penalty, and this is not a reasonable course of action.

by mlaci 6y ago

pkhamre 6y ago

So you're saying that generating a new password looses entropy?

setr 6y ago
Choosing is the problem here -- it's now only as random as your preference Eg the scheme doesn't do its job well if you don't know the word, so the dictionary can be reduced by that much
- ResidentSleeper 6y ago
  On the other hand, I'd wager that the set of words that you can recognize is vastly larger than the set of words that you're likely to come up with on the spot. Hence, using a generator would still result in higher entropy then trying to come up with a password yourself. Random numbers picked by humans are notoriously biased. I'm guessing it's even worse when you ask them to come up with random words.
mlaci 6y ago
Yes, if the regeneration depends on your preference of the generated words, the words order or link between them. The individual generations independent from each other, so if your choice – how many regeneration you do - not depends on the generations outcome, for example on your birthday date or favorite number, their randomness are equal. But randomness are not enough, it's possible the first generated version correlate with your preference and that situation does not really matter why are you stopped generating new password. Predictability of this scheme very good, because the strict rules. All implementation using common english words. For words smaller length, easy spelling, less ambiguity are preferred. Mixing nouns verbs and adjectives are more meaningful, order also adds more meaning. Word count very limited. Preference on the separator character also very rigid. Personal preference more known, because hidding your preference on all english words very hard and mostly unconscious.

mlyle 6y ago

A mild amount of regeneration doesn't hurt, though. If you generate 4 and pick your favorite, you've shaved less than 2 bits of entropy off.

mlaci 6y ago
It's just a bare minimum that you reduced, if you add some preference it's worse than that. I did some test, maybe I'm just lucky, but i got password with a word starting with b at the 3rd generation, and i got adjective-noun pair in that order at the 5th generation.
- mlyle 6y ago
  > It's just a bare minimum that you reduced No, it's the -maximum- that I reduced entropy by. If I choose randomly from 4 possible passwords, I've shaved off --no entropy--. If I choose with a strongly predictable preference (say, everyone knows I'll pick the password that's first alphabetically) I've shaved nearly 2 bits off the probable search space: you probably only need to look in the first 1/4th of the search space. Choosing with some subtle, individual preferences is something inbetween.
  - mlaci 6y ago
    > with a strongly predictable preference No, your example has nothing to do with preference, your method (picking out of 4) just less random than picking from one (the first). Preference is, when certain passwords more likely to be picked than others or at those passwords less likely to be stepped over to generating a new one. Wtih strong preference you regenerate until you got that preferred password, for example you prefer short words and the attacker know that, at first trying combinations with short words has better chance to cracking the password.
    - mlyle 6y ago
      You're just talking past me, bro. Regenerating and picking your favorite from a few is reasonable and isn't a big entropy penalty (the penalty is easily bounded). Infinitely re-rolling until you get the exact phrase "correct horse battery staple" obviously has a severe entropy penalty, and this is not a reasonable course of action.