How to remove password protection from compressed files

Question

This has always been a problem for me for a long time. Let's see if any SuperUser can solve this:

I have a directory in which there are lots of password protected .RAR files of which I know the passwords. I want to remove the password protection from all of them without extracting the contents. Since each file is larger than 1 GB, decompressing & then recompressing without password encryption is not a good option for me. How can I easily do that? I'm using WinRAR 3.80 on Win7. Any other 3rd party tools are welcomed.

Answer 1

Best solution (IMHO):

Use a DOS Batch file with the command FORFILES, to cicle all files, with the command to unrar with the password and thn rar it back up again without password. And finally delete the unnecessary files.

If I were you I would do it in python, for me it's less confusing then BATCH Files (*.bat), and you can find recepies for almoust all that you want to do, all you need to do is glue then togheter(the right way :) )

Answer 2

Since each file is encrypted using the passphrase/password, it logically follows that in order to un-encrypt you need the password, which you have.

But the files are encrypted, meaning without the password, they are seemingly random garbage.

If it were possible to merely remove passwords, without extracting, winrar's encryption would be broken (from my understanding, anyway).

So I don't really see how it is possible - just write a batch file to un-encrypt them all overnight.

Answer 3

WinRAR use real hard encryption. "Remove" password mean decrypt all data. I dont know, but wery possible encryption done in one operation with compression. Therefore "remove" password require decompression.