Ever run into the problem where you created a password protected zip/rar file and you forgot the password or accidentally deleted it? Or just don’t know the password at all? Well I have come across a nice solution for cracking zip/rar files. Its called rarcrack, If you forget your password for compressed archive (rar, 7z, zip), this program is the solution.
This program uses brute force algorithm to find correct password. You can specify which characters will be used in password generations.
tar xvjf rarcrack-0.x.tar.bz2 cd rarcrack-0.x sudo apt-get install libxml2-dev make ; sudo make install
rarcrack your_encrypted_archive.ext [--threads thread_num] [--type rar|zip|7z]
Everything in  are optional, rarcrack default crack two threads and auto detect the archive type. If the detection wrong you can specify the correct file type with the type parameter. RarCrack currently crack maximum in 12 threads.
After the cracking started RarCrack will print the current status of cracking and save it’s to a status file. If you want more specific password character set, you need to run RarCrack to create the XML status file (3 sec).
There will be a sample XML file, and you see there is a character set. If you want, you can modify this file and when you start RarCrack again the program will be use new variables.
Warning: Take care when you changing this file, make sure the current password don’t have characters outside the abc[character set]!
More information on rarcrack can be found here