Can I Remove A RAR File's (known) Password Without Recompressing The Archive?
Answer : 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 c...