fcrackzip is a zip-file encryption cracker, which can handle (recover / crack / hack) any password encrypted zipfile. Inside it uses a number of methods to accomplish the crack, but this happens nicely behind the scenes.
Install and fcrackzip on Ubuntu by typing:
cc@zeus:~$ sudo aptitude install fcrackzip
Use the fcrackzip for password cracking on Ubuntu by typing:
cc@zeus:~/Desktop$ fcrackzip -v -b -p aaaa -u cuda_dxtc.pdf.zip
found file 'cuda_dxtc.pdf', (size cp/uc 244965/294438, flags 9, chk a5d3)
checking pw rUt~
PASSWORD FOUND!!!!: pw == test
cc@zeus:~/Desktop$
Happy zip-file cracking ;)