Hello, I am having one issue. I have zipped a file few months ago but now I forgot its password.
There are three basic concepts here:

1. File compression ("zipping")
2. Password protection.
3. Data encryption.

It looks as if we have a compressed file with password protection here, but, as encryption is mentioned in the thread title, I suspect that we are looking at a .rar file, as I believe that they use the password to "scramble" the data in some way, if not truly "encrypt" it.

Obviously a compressed file is no problem so long as you use software that understands the compression method. The ones I use are WINRAR, Peazip and 7zip. WINRAR is a (morally) pay for product, but it is up to you, as all you get is a nag screen after the 40 day trial.

I haven't looked at this in many years, but DOS and then Windows came with a space saving compression utility. If you needed to open files on a hard drive that had been compressed using DOS you needed to run the exact same version of DOS. I don't know about Windows................

Anyways, a simple password protected file is relatively simple to crack.

Where you have a .rar file that is password protected it is another matter. Sure there is stuff on the internet that claims to do the job, but I would consider it to be mostly snake oil, and not worth paying for.

I don't care what software you have, If you give me a .rar file with a password of 15 characters or more I wouldn't even bother to attempt to crack it............ I would be looking at months if not years; and that is on my Phenom II x6 3.2~3.8GHz with 8GB of DDR3/1333MHz and SATA2 drives.

I believe that .zip files are somewhat simpler, but I have no idea by how much that is so.

Now, if you daisy-chained a dozen Playstation3 processors on a special rig with custom software it might be a slightly different story, but it would still take some time. ....................sorry, I forgot to bookmark a link to that article