4 ms·

Song lyrics are not safe https://arstechnica.com/information-technology/2013/08/thereisnofatebutwhatwemake-turbo-charged-cracking-comes-to-long-passwords/ https

Song lyrics are not safe https://arstechnica.com/information-technology/2013/08/thereisnofatebutwhatwemake-turbo-charged-cracking-comes-to-long-passwords/ https://arstechnica.com/information-technology/2013/08/there... I don’t know exactly where the breakeven point is, but there is some point where a song lyric or other phrase provides less entropy than a relatively short password. Bottom line: use a lot of random ascii characters(at least 14 or 16, or 4 random words) and you’re probably set. Use less, or a found phrase and it’s not good.

acdha 8y ago
You can't talk about safe without a threat-model, especially distinguishing between whether you're trying to prevent offline attacks against stored data or brute-forcing a running login system. If you can rate-limit many things are fine, especially if you have some confirmations at key points (“Your account was just accessed from …”) with restrictions which make it hard for an attacker to permanently wrest control of the account or incur large costs immediately after gaining access — think about how Amazon.com doesn't require 30 character passwords because adding a new shipping address requires you to re-confirm the credit card information first.
- hyperpape 8y ago
  That's definitely true, though you can simplify matters by saying "I'm always going to try to have passwords that are safe against offline attacks".
  - acdha 8y ago
    I would ask what’s the cost benefit ratio for defending against offline attacks with increasingly unpleasant password requirements versus things like increased KDF rounds, general server security improvements, and the defense in depth measures which increase the costs of actually profiting from a user account compromise. I think we’ve historically been shaped by classic Unix crypt() memories where something couldn’t easily be fixed without breaking compatibility even though that era is largely in the past.
    - hyperpape 8y ago
      I see how this wasn’t obvious, but I never actually said anyone should implement any particular password requirements, just that certain requirements might not increase entropy as much as you might think. My above comment about offline attacks was my personal stance/ideal: I use a password manager for just about everything, not something I’d mandate. As a developer, in many contexts I might implement min 8 chars with no special char requirements. I think the bad password check is also a good idea.

acdha 8y ago

You can't talk about safe without a threat-model, especially distinguishing between whether you're trying to prevent offline attacks against stored data or brute-forcing a running login system. If you can rate-limit many things are fine, especially if you have some confirmations at key points (“Your account was just accessed from …”) with restrictions which make it hard for an attacker to permanently wrest control of the account or incur large costs immediately after gaining access — think about how Amazon.com doesn't require 30 character passwords because adding a new shipping address requires you to re-confirm the credit card information first.

hyperpape 8y ago
That's definitely true, though you can simplify matters by saying "I'm always going to try to have passwords that are safe against offline attacks".
- acdha 8y ago
  I would ask what’s the cost benefit ratio for defending against offline attacks with increasingly unpleasant password requirements versus things like increased KDF rounds, general server security improvements, and the defense in depth measures which increase the costs of actually profiting from a user account compromise. I think we’ve historically been shaped by classic Unix crypt() memories where something couldn’t easily be fixed without breaking compatibility even though that era is largely in the past.
  - hyperpape 8y ago
    I see how this wasn’t obvious, but I never actually said anyone should implement any particular password requirements, just that certain requirements might not increase entropy as much as you might think. My above comment about offline attacks was my personal stance/ideal: I use a password manager for just about everything, not something I’d mandate. As a developer, in many contexts I might implement min 8 chars with no special char requirements. I think the bad password check is also a good idea.