Encrypted Archive Format

[bsiegel]

I just recently tried using PAE format to encrypt an archive for the first time, and I was actually quite surprised at the lack of concern for security, considering that PAE is designed for secure use. I am referring to the fact that PAE is basically a container format. It's fine for encrypting individual files, but as an encrypted archive format it is terrible.

The problem with this is that even when PA is set to handle archives transparently, when you go to open the PAE+archive file, PA must first extract the inner unsecured archive file to your temp directory. Of course PA deletes it once it is done, but if PA crashes (or is terminated) while running, the unencrypted archive file remains in your temp directory for anyone to find. And even after it is deleted, it would be trivial for someone to use a drive recovery program to retrieve the unencrypted zip file from your temp directory. Either way you look at it, while having an intermediate archive is a perfectly acceptable (and necessary) step for extracting from a .tar.gz, it is neither desireable nor acceptable for dealing with a secure archive.

Would it be possible to create a better format than PAE, made just for encrypted archives? Actually, perhaps you could just extend what you already have in PAE, but store the file list of the inner archive (encrypted of course) in the PAE header. That way, you could just read the header to get the list of all the files in the archive instead of having to extract the entire thing to a temp folder.

Also, I am not sure if this is possible with the various archive formats but perhaps you could make it so that when the user wants to extract a single file (or set of files) from the encrypted archive, you could use the file index in the header as an index into the archive and thus could extract them directly instead of extracting the entire inner archive first.

--bsiegel, registered user