Can I remove a RAR file's (known) password without recompressing the archive?

Question

I know the password to the RAR file as I locked it myself. Is there a way to do this in WinRAR or an equivalent program? The only thing I knew to do was to extract it, then create a new RAR without the password.

Answer 1

Out of the box, no, you can not. Version 3 of the RAR file format (implemented first in WinRAR 2.9) encrypts the actual data itself, as well as the file headers (if requested) using AES-128 encryption. With just WinRAR, it is impossible to simply "remove" the password from an archive, since the data itself is encrypted with the password.

You could make a quick batchfile implementing a "remove password" feature, which could simply unrar the archive, and then re-compress the files without a password.

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Technically, the data is compressed before being encrypted. This indicates that, given enough knowledge of the RAR file format itself, one could create a tool to AES-decrypt the datastream of the compressed files, and then save it into a new RAR archive. It should be noted, however, that this requires extensive knowledge of the file format itself.

Given the number of open-source tools that support password-protected RAR files (e.g. unar), one could learn how to do this by reading existing source code, and then using the decrypted, but still compressed, bitstream to generate a new RAR archive. However, this is far from a trivial task, as you would then have to rebuild the RAR header manually as well (or at least ensure the file format's compatibility).

Answer 2

Actually, I think a previous answer from another question already answers this:

You can do it by using this method . Tools > Convert Archives > Compression > General > Set Password > leave the password field blank > then click ok and save :)

But it re-compresses the archive.

There's no way around this; although practically speaking, the re-compressed archrive is identical to its previous compressed version (minus the password).

Answer 3

Since the question How can I remove the password on several RAR files at once? was marked as a duplicate of this question, here's how to remove the password on several RAR files at once:

Step 1: uncompress all RAR archives in their own folder (1 folder per archive) at once via 7-Zip, via right-click in explorer.exe -> 7-Zip -> Extract to *\.

Step 2: recompress each folder into their own RAR archive, select all the folders, right-click in explorer.exe -> WinRAR -> checkbox "Put each file to separate archive". Screenshot from journeybytes.com:

Answer 4

You have to decompress and then recompress into a new RAR file. Then simply delete the old encrypted file and you've got yourself a fresh new RAR package without the unneeded password.

Answer 5

Create a new unprotected RAR file (e.g. containing an empty folder), then open the old protected one.

Now drag the files into the new unprotected RAR. No extracting needed.

Answer 6

Or you can open the archive then rightclick on the file and choose "set default password" and then enter the password, this way you will never have to enter the password again anytime you want to open the file.