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> statement about dictionary words being really crackable Every time I see this statement I immediately think: which dictionary? There are more languages than

> statement about dictionary words being really crackable Every time I see this statement I immediately think: which dictionary? There are more languages than usual suspects (eg English, Spanish, French, Italian, German, Mandarin) and L1/L2 speakers of those make up sizable portion of internet users. Are Welsh/Hungarian/Slovak dictionary words really as easily crackable than English ones? If you have dictionary for those, yes, otherwise I suspect no.

FabHK 5y ago
So, yes.
- PostOnce 5y ago
  Exactly. I don't have to speak any of the languages on wikipedia to use wikipedia as dictionary for cracking. You can have every quote from every book, every place name, every wikipedia article, every song lyric, and a cheap GPU can buzz through it all ... fast. Kind of breathtaking that we have that power now, and kind of terrifying.
  - Aachen 5y ago
    This is exactly what I did for a research project in school: download Wikipedia, extract all combinations of iirc 2-5 words, do a few transformations like adding a lowercase variant and space-less variant, and run that set against the LinkedIn sha1 password dump. Quite effective for cracking passphrases that weren't randomly chosen words but an existing phrase.
- leavenotracks 5y ago
  Individual words then are easily crackable. But, take 3 long dictionary words chained together...easier to remember and more secure than a shorter randomly generated string. E.g. postcriptaluminumengagement vs kug45l2wx Or are there also dictionaries that contain combos of words?! (Would be rather a large dictionary).
  - Aachen 5y ago
    3 words is not enough usually, but it technically depends on the dictionary size. Since the formula is dictsize^numwords, adding a word to your phrases is a lot better than adding a thousand words to your dictionary (also because of diminishing returns above ~5 thousand words). Iirc 6 words is a good size for most dictionaries or 7 words for diceware, but might be off by one so please look around. I remember posting it on the security stackexchange site (I'm currently on mobile, not logged in or I'd look it up in my user) and I'm not the only one who's done this calculation. It also depends on what security level you need (e.g. should it prevent from offline brute force or only online brute force)
    - freemint 5y ago
      Why are you assuming the advesary knows what dictionary is being used?
      - Aachen 5y ago
        Because there are only so many words in the world and an English person isn't going to use a Dutch dictionary. At that point it's going to be harder to remember than just random characters of the same entropy.
  - FabHK 5y ago
    > E.g. postcriptaluminumengagement vs kug45l2wx If you pick from a dictionary of 250,000 words, that is around 18 bits. So three randomly chosen words strung together give you around 54 bits. On the other hand, an alphanumeric character is around 6 bits, so 9 of them strung together is about 54 bits. Assuming your dictionary was 250,000 words, both of the passwords you posted were about the same quality (until you posted them - now they're again about the same quality, but much less). > Or are there also dictionaries that contain combos of words?! Your software just concatenates words and other well known sequences (123, zxcvbn). Check out the great password entropy checker called zxcvbn: https://github.com/dropbox/zxcvbn https://github.com/dropbox/zxcvbn https://dropbox.tech/security/zxcvbn-realistic-password-strength-estimation https://dropbox.tech/security/zxcvbn-realistic-password-stre... https://www.bennish.net/password-strength-checker/ https://www.bennish.net/password-strength-checker/ (Note: don't enter production passwords into random websites, needless to say...)
mr_mitm 5y ago
If the hash is weak enough that you can afford massive wordlists like crackstation [1], then yes, those words will be in the list. [1] https://crackstation.net/crackstation-wordlist-password-cracking-dictionary.htm https://crackstation.net/crackstation-wordlist-password-crac...

FabHK 5y ago

So, yes.

PostOnce 5y ago
Exactly. I don't have to speak any of the languages on wikipedia to use wikipedia as dictionary for cracking. You can have every quote from every book, every place name, every wikipedia article, every song lyric, and a cheap GPU can buzz through it all ... fast. Kind of breathtaking that we have that power now, and kind of terrifying.
- Aachen 5y ago
  This is exactly what I did for a research project in school: download Wikipedia, extract all combinations of iirc 2-5 words, do a few transformations like adding a lowercase variant and space-less variant, and run that set against the LinkedIn sha1 password dump. Quite effective for cracking passphrases that weren't randomly chosen words but an existing phrase.
leavenotracks 5y ago
Individual words then are easily crackable. But, take 3 long dictionary words chained together...easier to remember and more secure than a shorter randomly generated string. E.g. postcriptaluminumengagement vs kug45l2wx Or are there also dictionaries that contain combos of words?! (Would be rather a large dictionary).
- Aachen 5y ago
  3 words is not enough usually, but it technically depends on the dictionary size. Since the formula is dictsize^numwords, adding a word to your phrases is a lot better than adding a thousand words to your dictionary (also because of diminishing returns above ~5 thousand words). Iirc 6 words is a good size for most dictionaries or 7 words for diceware, but might be off by one so please look around. I remember posting it on the security stackexchange site (I'm currently on mobile, not logged in or I'd look it up in my user) and I'm not the only one who's done this calculation. It also depends on what security level you need (e.g. should it prevent from offline brute force or only online brute force)
  - freemint 5y ago
    Why are you assuming the advesary knows what dictionary is being used?
    - Aachen 5y ago
      Because there are only so many words in the world and an English person isn't going to use a Dutch dictionary. At that point it's going to be harder to remember than just random characters of the same entropy.
- FabHK 5y ago
  > E.g. postcriptaluminumengagement vs kug45l2wx If you pick from a dictionary of 250,000 words, that is around 18 bits. So three randomly chosen words strung together give you around 54 bits. On the other hand, an alphanumeric character is around 6 bits, so 9 of them strung together is about 54 bits. Assuming your dictionary was 250,000 words, both of the passwords you posted were about the same quality (until you posted them - now they're again about the same quality, but much less). > Or are there also dictionaries that contain combos of words?! Your software just concatenates words and other well known sequences (123, zxcvbn). Check out the great password entropy checker called zxcvbn: https://github.com/dropbox/zxcvbn https://github.com/dropbox/zxcvbn https://dropbox.tech/security/zxcvbn-realistic-password-strength-estimation https://dropbox.tech/security/zxcvbn-realistic-password-stre... https://www.bennish.net/password-strength-checker/ https://www.bennish.net/password-strength-checker/ (Note: don't enter production passwords into random websites, needless to say...)

mr_mitm 5y ago

If the hash is weak enough that you can afford massive wordlists like crackstation [1], then yes, those words will be in the list. [1] https://crackstation.net/crackstation-wordlist-password-cracking-dictionary.htm https://crackstation.net/crackstation-wordlist-password-crac...