forgotten password for zipped WinRAR files? pls help

Tattooed · 5 Dec 2010 at 23:45

Hi,
I have forgotten the passwords for zipped WinRAR files. Are there any free programs the will let me crack the password?

mrk · 6 Dec 2010 at 11:59

WinRAR passowrd crackers exist but they use brute force.

Prepare for an ice age to pass before you crack a long multi-character password.

Azuse05 · 6 Dec 2010 at 12:14

GPU acceleration helps, but it depends how complicated you made the pwrd

J.B · 6 Dec 2010 at 12:31

Indeed, how complicated was the password? All lower case and only 4 characters? 10 characters using a-b, A-B, 0-9 and loads of punctuation?

Tattooed · 6 Dec 2010 at 15:38

Hi,
Thanks for all the replies. I think the password was about 10 characters long.

mrk · 6 Dec 2010 at 15:42

WinRAR uses 128bit AES encryption for passworded RAR archives. Cracking a 10 character non dictionary password is not an option. You might as well buy a lotto ticket

Aod · 6 Dec 2010 at 15:45

Encryption where you forget the password = Delayed deletion.

fullmetaltony · 6 Dec 2010 at 15:51

If it's a dictionary word you might have a chance, but as Khaaan says, it's not an option otherwise as you're looking at a hell of a long time to crack it, even if it's just lowercase.

Search google for zip file crackers and have a fiddle with one, it'll soon become apparent you're looking at years to go through all the permutations.

Cuchulain · 6 Dec 2010 at 15:51

10 char. password comprised of only letters will take around 172 days to crack using brute force, make yourself comfortable.

asim18 · 6 Dec 2010 at 15:54

Cuchulain said:
10 char. password comprised of only letters will take around 172 days to crack using brute force, make yourself comfortable.

What if you have this at your disposal?

Cuchulain · 6 Dec 2010 at 16:02

asim18 said:
What if you have this at your disposal?

Modern CPU's aren't really ideal for password cracking, you want dedicated FPGA's, but I reckon utilising all 17,000 processors might speed it up a touch.

mrk · 6 Dec 2010 at 16:07

This is why GPUs are far better and why the US military has a cluster of Playstation 3 consoles crunching away

Speed · 6 Dec 2010 at 16:16

Wasn't there something in the news recently about using a GPU to speed up password cracking quite significantly? Some sort of software that a group of British guys came up with...

yashiro · 6 Dec 2010 at 20:56

This is why GPUs are far better and why the US military has a cluster of Playstation 3 consoles crunching away

They don't use them because of the crappy RSX GPU. They use them because of the power/performance ratio of the Cell CPU's.

J.B · 7 Dec 2010 at 08:07

If you have a fairly modern nVidia GPU you could use one of the password attacks that use CUDA, might speed things up a little bit.

Azuse05 · 7 Dec 2010 at 12:06

Actually gpu accelerated password cracking has worked on both ati (amd) and nvidia for a long time, it's simply faster on nvidias chips. In fact there's a russian company that's been producing just such tool in the event you "forget" your wifi password

I know they make something for zip files, I just cant find it.

Chaos · 7 Dec 2010 at 14:58

Could try booting up a linux distro and trying rarcrack.

Relentless81 · 7 Dec 2010 at 15:06

But in the movies they just type it out?