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How Many Seconds Would It Take To Crack Your Password?
DillyTonto writes "Want to know how strong your password is? Count the number of characters and the type and calculate it yourself. Steve Gibson's Interactive Brute Force Password Search Space Calculator shows how dramatically the time-to-crack lengthens with every additional character in your password, especially if one of them is a symbol rather than a letter or number. Worst-case scenario with almost unlimited computing power for brute-forcing the decrypt: 6 alphanumeric characters takes 0.0000224 seconds to crack, 10 alpha/nums with a symbol takes 2.83 weeks."
That's why you enter something lexically similar to it and not the actual password. /. password is 3 mid-length words and the number 54 added to it, you type in that many letters and the number 11.
If your
Got "trillion trillions centuries" here :)
Which really means "lasts until some idiot stores it as plain text."
What a great way to generate a new wordlist...
What system would allow someone to make thousands of attempts per second to login?
That's not the problem. The problem is that the lists of user logins and corresponding hashed passwords get in the wrong hands, whether it be due to bad design and/or coding, insecure software, or unfaithful servants. When you have that list, you run brute force against it to get the actual passwords.
Breaking into servers is much more attractive than breaking individual user accounts, simply because the yield is so much higher. Make a good trojan delivered through good social engineering, and you may catch 1% of the users. Breach the server, and you get the account info of all of them, and by running a crack session, you likely have 20-50% of the passwords within hours. Choose a very hard to crack password, and they may never get it even if they have the hash.
This happens a lot more than what we think. A server breach doesn't have to leave traces that anyone actually sees. We mostly know about the cases where the culprits brag about it or publish lists, which is unlikely to be more than the tip of the iceberg.
Companies are going to insist that their data is safe until proven otherwise, but you're stupid if you believe them.
Sony, Steam, LinkedIn, eHarmony - there are hundreds of server breaches with stolen user/hash lists that we know about. And likely an enormous amount we don't know about.
All that is useless when the server gets compromised and the username/hashed password list gets sold to the highest bidder.
I wrote a nice long reply rebutting every single point then lost it when I hit backspace and focus was in the wrong part of the window. Grrr.
The author gets lots of things confused:
- He seems unaware that a rainbow table is equally effective against a good password as a bad one.
- He seems to think a dictionary attack comprises wholly and exclusively of words taken from a dictionary with no added numbers, symbols or punctuation. Bruce Schneier doesn't seem to agree with this, and I'm far more inclined to believe Mr. Schneier.
- He believes that a likely avenue for attack is constantly guessing a given user's password on a website. Any half-sane web service will block you long before you've tried a few thousand passwords against one username.
- He fails to note that in the case of LinkedIn, the list of password hashes itself was leaked - and this is Bad News.
- He also fails to note that in the case of LinkedIn, the password hashes were unsalted - Much Worse News.
- He also fails to note that if an unsalted list of password hashes is leaked, then it doesn't really matter how strong your password is, it's going to get found rather quickly. There's very little you or I can do about this. You could refuse to use systems that have such terrible security, but usually you only learn their security is this bad when it's far too late.
- He tops it off by recommending 10 character passwords with symbols and/or numbers. In other words, he falls foul of the problem described by Randall Munroe in XKCD some time ago.
You don't ask about your actual password. You check one that's similarly complex.
However, I noticed that he's not *checking* a dictionary file when evaluating password strength. The actual strength of a password like "spastic-elongated-kremlinitude" is pretty good, but his checker's figure of four hundred thousand trillion trillion centuries to crack with a high-end cluster is optimistic beyond the bounds of all reason. That would be naively building it up character by character, and *nobody* does naive character-by-character brute forcing for passwords that long. That's like building a skyscraper without power tools.
Cut that out, or I will ship you to Norilsk in a box.
let's say you know 100% for sure that somebody is using xkcd's method.
there are 15,222 words in the english language according to oxford english dictionary. how many are common 5, 6, and 7 letter words? hard to say for sure. I think 3000 or 4000 would be a good conservative guess, what do you think? let's say 3000 to err on the side of caution.
how many combinations of common 5,6, and 7 letter words does that give us to build a password based on xkcd's suggestion?
3000^4
that's 8.1 x 10^13 discrete combinations, counting the ability to reuse the same word.
I'm asuming you didn't build a plaintext dictionary with all those possible combinations... at 1 byte per letter, and an average of 6 bytes per component word, that's 4.86 x 10^14 bytes, or a 442 terrabyte dictionary file. where the hell are you storing that?
no, i'm assuming you probably built a program specifically to build combinations of component words and brute force using that. sure that will eventually work, after it goes through its 8.1 x 10^13 itterartions (worst case)... but hell, why are you trying to crack that hard a password when there are thousands out people out there whose password is just "Password1"? the club doesn't make your car theftproof, it just makes it less inviting to the thief than the car next to it. you don't need to outrun the lion, you just need to outrun the slowest person in your group.
and this is all assuming:
1. you somehow -know- which password generation method the person is using
2. they didn't do what I do with that method, and throw a few uppercase and numbers in there anyway.
Pretty much everything you wrote is wrong other than your first line.
5 random lower case characters + one upper case = 52^6. It would be 26^6 if and only if you knew exactly where the upper case letter was, which is an unreasonable assumption. Adding an upper case letter would eliminate a straight lower-case dictionary attack entirely and double the pool of possible characters from 26 to 52. There are 6 places, so 52^6.
You make the same mistake in several other locations.
To address your other claim, "Adding one extra capital, number or symbol to a password does not increase password strength that much." ... You make this claim only because your math is so hilariously wrong.
Based on what? You're arguing that Gibson is wrong, but your reasoning amounts to saying "nuh-uh".
The attacker knows that there are 6 characters in a password. Or does he? I'd want a hashing algorithm that hides the password length by turning any password length into e.g. a 64-character hash.
Even assuming he knows it's 6 chars, how can he know there are 5 lowercase + 1 uppercase? Assuming the hash doesn't give clues (which would be a weakness in the hash function) I see no way the attacker can infer 5 lowercase + 1 uppercase (and guess correctly at which position the uppercase will be).
Therefore he has to assume a search space of lowercase+uppercase for all positions, which leads to 52^6.
5 random lower case characters + one upper case = 26^6 * 6.
6 random case random characters = 26^6 * 2^6 = 52^6.
Check your own math first.
with almost unlimited computing power for brute-forcing the decryptt: 6 alphanumeric characters takes 0.0000224 seconds
With "almost unlimited" computing power any password will almost take "almost no time" to decrypt.
sic transit gloria mundi