The developer provides some plain numbers to show the effectiveness of using the GPU to recover a rar password with four characters:

• ~168 passwords per second on single core of Q6600 @ 2.4Ghz (crark’s result)
• ~325 passwords per second on 8600 GT
• ~3120 passwords per second on ATI HD4850
• ~2075 passwords per second on GTX260/192SP

The performance of the listed ATI card is almost 20 times that of a password recovery where only the cpu is used. The password recovery software is a command line utility and the developer is offering extensive information on the possible parameters that can be used to recover the password. The suggested length of the password should not exceed six characters although it is theoretically possible to start a password recovery for a password with up to 17 chars.

The basic command for the password recovery is:

igrargpu.exe [switch:param] filename.rar

The command

igrargpu.exe /a:b /c:s /min:1 /max:4 archive.rar

will for example check all four letter combinations of lower case Latin characters. Known characters of the password can be added to the command to speed up the recovery attempt.It is advised to check the readme for a detailed overview of all possible parameters. The password recovery program can also use a dictionary based attack with rules. RAR GPU Password recovery should work on most versions of the Microsoft Windows operating system. The portable software is available for download at the developer’s website.