How to find the Password of RAR Archived Files?

Question

Is it possible to find password of files inside RAR archive, that I have uncompressed files outside that archive and the files are exactly the same as in the archive?
Summary: How to find the Password of RAR Archived Files?

Solution 1

Unfortunately, you cannot easily obtain the password of a RAR archive.

The fact that you have the uncompressed and the corresponding compressed files next to each other, does not help with cracking the password.

The only reliable way to know the password is to use brute force and try out all possible combinations. With a modern computer, you might try thousands of passwords every second, but depends on the length and complexity, the real password might still take ages to crack. Of course, if you created the password yourself, you could perhaps know the length, or know which characters might be included in the password. That could shorten the time it requires to crack it, but in general, it is a very time-consuming task.

Solution 2

Yes. You can brute-force attack the passwords using a tool like the RAR GPU Password Recovery tool. I haven't tried out this tool, mind you, and brute force attacks can take quite a while, even if using a highly-optimised tool.

Comments

[Oliver Salzburg]

It should also be noted that every single file in a RAR archive can be encrypted with a separate password. I don't think that it utilized often though.

[pbies]

Thank you guys for your answers. I know the brute-force way, but I wasn't sure about the single file inside and outside the archive. I was trying the brute-force way, but the password is very long (small letters and digits only), I couldn't get reasonable speed on my two-GPU computer. Applications are not satisfying me (use all cores and threads of CPU and two GPUs, or it is not working at all). Faster would be to write own code to do that, but I don't know maths enough.