I have this file I've uploaded to some server few years ago.
just in case someone will break into that server, I've used some archive program and choose cbz file format and set a password.
anyway, i now need to open the file but i can't remember the password.
It's not life or death situation, it's just something private and nostalgic and i can probably get that file from some external hd i have, i tend to backup allot.
but out of curiosity,
in real life situation, how do you crack an archive with password?
is there a way to determine the type of encryption? i'm guessing that this is pretty important to start the cracking.
and after that, can i use john for this type of mission?
i know all my password protected file will always be at least 8 characters long and i don't use capitol/spacial characters.
so that's a start.
but i do need need some first direction

Please re-read the LQ-Rules:

In such cases you better collect all the information you can remember and decide: either find another backup or find the password. And last but not least find a better way to not lose your files (next time). As it was mentioned noone will help you to crack, but you may find a solution.

Actually I have a .fca file containing some important data for me, and I was unable to open it using debian. I found it was created by the tool finecrypt many years ago. Its home page is already over, so I could not find support. Finally I found an installed version in my old and unused XP partition and I could also start it with wine. I also knew the password, so finally I could open that file.

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even that my question is about password cracking, I don't think that it really breaks any rules.
it's nor like I've asked someone to do anything, give me link to some pirate cracking software or anything of the sort.
No file was uploaded to be cracked and no links was asked to cracking software.
just trying to understand a subject and everything is just theoretical.
In my opinion it's not different from a guy who forgot his root password and asking for a way to bypass it.
Now with that said, if I truly broken LQ rules, accept my apology and feel free to close the subject.

well, thanks for the reply. actaully already got the password after trying allot of the passwords i use.
nevertheless, still intrested in the machnesem of password cracking. the subject it self is intresting. so i guess i need to do some reading about it.

There is a difference: to restore the root pw you need access to the hardware and console, you will hardly be allowed to access any host but yours. Cracking a file is a quite different issue...

Basically, "password cracking" i.e. by brute-force really is a Faustian quest. There are simply too many possibilities, if the user in question avails himself or herself of them. Even the slightest departure from "a word in the dictionary, all lower-case" makes the number of possibilities unreasonably large.

Nevertheless, human psychology is the weak link here: the most commonly used password in the world is: password. The second most common one is: enter. The third: login. Or so they say. (YMMV.)

If you seriously want to secure something, the best way to do it is to use public-key cryptography: generate a digital certificate (issued to only one person or computer, for only one purpose), then encrypt it with a password. Even if the password is discovered, the key can be selectively invalidated and replaced. This is precisely the same way that people work with, say, badges in an office-building. (Have you ever walked toward the elevators in such a building and been stopped by someone who asked, "what's the password?" No. You flashed your badge.)

Help with cracking is not a valid LQ topic. Thread closed.