After this forum got hacked theymos, the guy who runs this forum, posted this information about how long it would take the hacker to recover a password from the hash of it that he stole. If the password consists of normal words it's possible. If the password consists of 12 random characters it would take 260 years to crack one password.
I don't know what software or equipment people use to crack passwords but you can prevent your account from being hacked if you make sure your password consists of 15 or more random characters like numbers, upper and lower case letters, and special characters.
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The following table shows how long it will take on average for a rather powerful attacker to recover
RANDOM passwords using current technology, depending on the password's alphabet and length. If your password is not completely random (ie. generated with the help of dice or a computer random number generator), then you should assume that your password is already broken.
It is not especially helpful to turn words into leetspeak or put stuff between words. If you have a password like "
w0rd71
Voc4b", then you should count that as just 2 words to be safe. In reality, your extra stuff will slow an attacker down, but the effect is probably much less than you'd think. Again, the times listed in the table only apply if the words were chosen at random from a word list. If the words are significant in any way, and especially if they form a grammatical sentence or are a quote from a book/webpage/article/etc., then you should consider your password to be broken.
Estimated time (conservative) for an attacker to break randomly-constructed
bitcointalk.org passwords with current technology
s=second; m=minute; h=hour; d=day; y=year; ky=1000 years; My=1 million years
Password length a-z a-zA-Z a-zA-Z0-9
8 0 3s 12s 2m
9 0 2m 13m 3h
10 8s 2h 13h 13d
11 3m 5d 34d 1y
12 1h 261d 3y 260y
13 1d 37y 366y 22ky
14 43d 1938y 22ky 1My
15 1y 100ky 1My 160My
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1 word 0
2 words 0
3 words 0
4 words 3m
5 words 19d
6 words 405y
7 words 3My
......
