Hacker News Reader

Comment by Blikkentrekker | Hacker News Reader

What I've been wondering for a long time is how do these two passwords compare:

   hiKxChDiaHNAtgVz

vis-à-vis:

   kähdikyylkönekkimahdakerttaksa

One is a 16 random `[a-zA-Z0-9]` characters, the other is a 32 character long nonce word, containing <ä> and <ö> among others that conforms to Finnish phonology, but otherwise is devoid of any meaning and phonology but easier to remember to speakers of Finnish. One is a 16.

Does 32 characters opposed to 16 offset that the latter conforms to the phonology of a language with 6 million speakers?

View on HN

It depends on your threat model. The simplest analysis assumes that the attacker knows how you are generating your password.

There are 36^16 possible passwords with the first scheme. I don't know how you generated the second. One way of doing it would be to generate all valid Finnish syllables and select randomly from that. If the number of possible syllables raised to the power of the number of syllables in your password is greater than 36^16, then it's more secure.

Minor nitpick: there are 62^16 possibles passwords in the fist scheme (passwords are case-sensitive in almost every scenario).

It can IMO. The right thing to do is to consider the entropy in a pessimistic attack context. Enough dictionary-attackable words together still has good entropy

I wonder if the xkcd comic about this is still accurate, being that it's generally safer to have longer passwords regardless of how it's formatted.

https://xkcd.com/936/

I recently signed up for a ticketing website to buy tickets for a concert and was appalled that the site wouldn't accept my 50+ character generated password... I had to enter something between 8 and 15 characters.

Still seems to me that "^Zh7*2wNfRG7ehj" would still be inherently less secure than "thisisasuperlongpasswordandithas12345alotofcharactersinitthatwouldtake12345rainbowtablesalongtimetocalculatefor"

15 vs 111 characters to find permutations for.

That is, of course, even assuming that the password db for the site is even hashed (AND salted) or not.

> I wonder if the xkcd comic about this is still accurate, being that it's generally safer to have longer passwords regardless of how it's formatted.

Indeed, that is what I am wondering. If the double length offsets that it is not random.

Twice the length is quite a lot, but it's also not random any more.

The comic is still accurate and always will be. It's just a mathematical law, even though it uses a popular display of it.

What you are wondering about is the size of base of the exponentiation. Let's look into that.

If you use individual, unrelated letters, this is 26 (or 52 when you allow uppercase, or 62 if you also allow numbers). At e.g. 12 letter, this is 62 to the power of 12. At 16 letters, it is 62 to the 16.

If you use words (as the comic proposes), then the dictionary size will be the base (in this case, 4000 or so). You have fewer words, so entropy is 4000 to the 4.

If you use phonologically grouped words or syllables, the base size is their number. I'm not a linguist, but I'd guess it is somewhere around 100 or so. If a syllable is 2 to 3 letters long and you use 32 letters, you get something like 12 syllables. Entropy is 100 to the 12.

The second password can fail quite quickly assuming an attacker is going to target Finnish words to perform a dictionary attack, perhaps a Finnish website makes sense for something like this to be done.

Psuedo-random is always better because anything else usually follows a pattern that can be exploited(sequence, structure, words, statistical bias)

If we can't make assumptions about the secret, the only solution is plain brute-force when it comes to the number of characters squared the length of the password.

As I said; it's not a word.

It isn't a word and has no actual meaning or morphology; it's comparable to something such as:

   wrockrangnattentamploozakoshal

It conforms to Finnish orthography and phonology, but otherwise not a word.

It seems to be though that it is consisted of some structured elements(I don't know much about Finnish orthography\honology)

So if it has some predictable structure, statistical attributes etc, it can be exploited to reduce the search space and therefore can be weaker than the actual raw entropy.

Does that matter in the real world? I don't think so.

Yes it can, so I wonder if the double length offsets that.

I would assume that assuming an attacker knows that it is nonce Finnish, that he would be able to craft a specific algorithm that is faster than 32 random character for specifically this, but that in practice if he not know that with all modern approaches it is æquivalent to attempting to bruteforce 32 characters, giving priority to letters and vowels, especially with the inclusion of <ä> and <ö>.

Again, it is hard to compare because I don't know enough about Finnish.

the first option is rather simple, assuming we have a good psuedo-random generator with low bias margins. we get:

A-Z,a-z,0-9 = 58 options, Length = 16

58^16/2 is the target.

Second option is weaker IMO because we know that plain brute-force is rarely being used today for anything over 13~14 characters.

We mostly use masks\dictionaries to try common passwords, phrases, sequences. So even if there's a very small chance that someone would have some kind of heuristic rule that targets Finnish orthography\honology, it is still more likely than someone successfully brute-forcing 16 random chars+numbers.

Another interesting observation is that fact that it contains common English words by chance. things like rock or tent. those can increase the chance of a dictionary success(our 32 chars starts breaking apart) whereas the 16 chars are random so in nature there are less prone to contain common English words

Reply on news.ycombinator.com