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Long title. Anyway, I haven't been able to find an answer to this question.

I know the password to the RAR file, I locked it myself, but now all I want to do is remove the password because it's too much of a pain in the butt to type it in every time. 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.

It's not a life-or-death issue, but it would be nice to know. Thanks for your time!

EDIT: I just saw a bunch of related questions that appear to ask the same thing. The only solution I saw was using a DOS command to yadda yadda yadda. Here it is: How to remove password protection from compressed files

Is there an easier way? Thanks again!

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2  
First, those aren't DOS commands, they're just running programs with some command-line arguments. Second, all those commands do are extract the archive, delete it, and re-compress the files again. This is the only way to do what you want, see my answer below. –  Breakthrough Aug 30 '11 at 14:50
    
What @Breakthrough said - that's just unpacking and repacking them, it even says so explicitly. This is the only way to do it. –  Shinrai Aug 30 '11 at 14:51
    
Thanks, guys! I see now. I didn't check it out thoroughly. –  Abluescarab Aug 31 '11 at 3:11
    
It's good that you're writing it's a "nice to know" question, because in the time it took you to write this you could've unpacked/repacked ;-) –  Jan Doggen May 17 '13 at 8:28

4 Answers 4

up vote 12 down vote accepted

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.


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).

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No, logically, it should be possible to decrypt the data without decompressing it, because it's encrypted compressed data, not compressed encrypted data. (the latter is fundamentally impossible, due to entropy increases from encryption). It's just an obscure enough thing to want to do that it's omitted. –  Random832 Aug 30 '11 at 18:00
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Right. If he had just PGP encrypted the RAR, he could have easily decrypted it without recompressing it. –  smackfu Aug 30 '11 at 20:57
    
Well, thanks for explaining it! It's rather disappointing, because I honestly believe this should be a feature, but I suppose not enough people want this feature to justify including it. –  Abluescarab Aug 31 '11 at 3:20
    
@Random832 yes sorry, I see that was poorly worded now. I updated the answer just now to hopefully get my thoughts across a bit more clear. After further research, this does to be technically possible given enough knowledge of the RAR format... Although as you said, obscure enough to be omitted (not to mention the proprietary nature of the RAR format complicates things). However, if anyone does want to get into it, I provided a link to an example open-source tool (unar) which can decrypt encrypted RAR archives. –  Breakthrough Aug 2 '13 at 13:34

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.

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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.

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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.

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protected by Breakthrough Aug 2 '13 at 13:35

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