I have some files I was given by my teacher at University, I could chase him up, but I may as well try getting blood from a stone, his response rate isn't great and I completed my degree a year ago!
They're pdf files stored inside password protected zip files. The passwords are networking related, have upper and lowercase and numbers, but no special characters as far as I remember, and some are permutations of each other "passwordL1", "l2Password" etc.
What are the different encryption algorithms employed by .zip files?
How can I determine the protection in use on my zip files?
Where can I find good papers and tools, which will ultimately give me back the pdfs which are annoyingly hidden by the password?