Quote from: KimNam on June 26, 2014, 03:25:32 AM

he can try password combination that he remembered
if it can't open, then he should forget it and take a lesson from that experience

If he can remember part of the password, he may ask others to brute force the password for him.
https://bitcointalk.org/index.php?topic=85495.0 (Not endorsing the service)

But it won't work if the "unknown" part of your password is too long.
https://bitcointalk.org/index.php?topic=85495.msg4401257#msg4401257

Quote from: Revalin on January 09, 2014, 03:09:54 AM

It's not feasible to guess completely random passphrases. Here are how many days it it will take with one CPU:

Code:

passphrase length lowercase alphanumeric any character
1 0.00 0.00 0.00
2 0.00 0.00 0.00
3 0.00 0.03 0.10
4 0.05 1.71 9.43
5 1.38 106.03 895.58
6 35.75 6574.10 85080.08
7 929.61 407594.28 8082607.59
8 24169.80 25270845.55 767847721.40
9 628414.78 1566792424.34 72945533532.94
10 16338784.22 97141130308.84 6929825685629.39

Even with a large budget (thousands of CPUs or GPUs) you could only do 6 or 7 characters.

It's only possible to crack a passphrase when you know most of it and the unknown part is constrained. That's why I have so many custom tailored scripts in this thread - each targets a narrow pattern which could be identified.