7 ms·
> A modern consumer GPU can crack "four random English words" in a day. Let's run the math: EFF's long wordlist[0] (the one used by Bitwarden's passphrase gen
by bilkow 1mo ago
> A modern consumer GPU can crack "four random English words" in a day.
Let's run the math:
EFF's long wordlist[0] (the one used by Bitwarden's passphrase generator) has 7776 words, which is about 13 bits of entropy per word (log2(7776) = 12.92). A 4-word passphrase then has 51.7 bits of entropy, meaning there are 2^51.7 possible options for the passphrase, which is 3.66E15 possible options.
For reference, a password with all completely random characters and symbols, for each character you have 70 possibilities, or about 6 bits of entropy. An 8-character completely random password (no words or the usual patterns) then has about 49 bits of entropy, which is less than a 4 word passphrase.
About the time it takes to crack it, assuming you can test an average of 1 password per μs (you probably can't, as passwords are usually stored using key derivation functions[1][2] with work factors tweaked for current hardware) it would take ~116 years to crack it. I usually see 5-passphrase recommended nowadays, which would multiply the required effort by 7776.
Sure, a 16-character random password has a lot more entropy, but it's also a lot harder to interact with (reading, comparing, typing) if you end up needing to, and it's still easier to crack than an 8-word passphrase.
[0] https://www.eff.org/dice https://www.eff.org/dice
[1] https://en.wikipedia.org/wiki/Key_derivation_function https://en.wikipedia.org/wiki/Key_derivation_function
[2] https://cheatsheetseries.owasp.org/cheatsheets/Password_Storage_Cheat_Sheet.html https://cheatsheetseries.owasp.org/cheatsheets/Password_Stor...
- applfanboysbgon 1mo ago[flagged]
- mr_mitm 1mo ago> most software in the world uses a basic hash like MD5 or SHA-256 rather than a key derivation function For passwords? Where do you get that information?
- applfanboysbgon 1mo agoExperience? Looking at codebases? The one in question does, in fact, use SHA-256. HN is a bit of a bubble because there's a large demographic of FAANG-tier employees here who work at big tech or unicorn startups, but most software in the world is not made by FAANG or unicorn startups, and the standards are way, way lower than you might think they are if you're used to living in this bubble. For software development practices in general, not just password storage. I think it's taken for granted that every single person on HN uses VCS, but even that is a luxury in many real-world working environments outside of SV. Even if only 10% of the services you use use MD5/SHA-256 (although I certainly would expect it to be >50% if we could do a large-scale study), why accept your password being easily compromised 10% of the time?
- pbhjpbhj 1mo ago>why accept your password being easily compromised 10% of the time? Those services using md5 aren't doing important things, I hope, so the password for that service hardly matters. If it does matter, then user long passwords/phrases and rotate every time (or find a better supplier).
- wavemode 1mo agoWhat you said: > A modern consumer GPU can crack "four random English words" in a day What you're saying now: > My mid-tier laptop GPU can crack the usual wordlist in under 12 hours against MD5 (46 billion guesses per second) So your response to the plain mathematical fact that, no, your consumer GPU cannot crack "four random English words" in a day, is that your consumer GPU can crack four words chosen from a list of a few thousand, in a day. Followed by personal attacks. Okay.
- deleted 1mo ago[deleted]
- BenjiWiebe 1mo agoWell, there could be quite a range of performance between a mid-tier laptop GPU (his consumer GPU), the average consumer GPU, and the average (gamer's) consumer GPU.
- drdexebtjl 1mo agoGreat, then use 5 words instead. Trying to pick a strong password assuming the service you’re signing up for doesn’t care about security is pointless. You’ll be pwned regardless of what you do.