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

[TBGBe]

Originally Posted by bsiegel

... PAE is basically a container format. It's fine for encrypting individual files, but as an encrypted archive format it is terrible...

Yes, it is a "container format", PAE is NOT "an encrypted archive format" - see the help file.

All PAE claims is that access to the archive is secured.
This is intended for security of file transfer - not working with the archive contents.
Even when using a format specific security (e.g. ZIP AES) which encrypts the individual files within the archive, once you have entered the password to decrypt - you are responsible for the "security" of the decrypted contents.

[spwolf]

Originally Posted by TBGBe

Yes, it is a "container format", PAE is NOT "an encrypted archive format" - see the help file.

All PAE claims is that access to the archive is secured.
This is intended for security of file transfer - not working with the archive contents.
Even when using a format specific security (e.g. ZIP AES) which encrypts the individual files within the archive, once you have entered the password to decrypt - you are responsible for the "security" of the decrypted contents.

Terry is right, PAE is an container encryption. This also has some benefits. It was done before we had 7zip AES and zip AES. It is same as if you encrypted archive with some stand alone encryption tool.

So, if you want real file format encryption, you have an option of 7zip AES and zip AES, both 256bit, and they work great.

[bsiegel]

I realize that PAE is designed to be an encrypted container format and nothing more. I'm not indicting the PAE format. What I was wondering was whether there would be merit to extending the PAE format to better handle encrypted archives. I'd be willing to lend a hand with it if you feel it would be worthwhile.

--bsiegel

[spwolf]

Originally Posted by bsiegel

I realize that PAE is designed to be an encrypted container format and nothing more. I'm not indicting the PAE format. What I was wondering was whether there would be merit to extending the PAE format to better handle encrypted archives. I'd be willing to lend a hand with it if you feel it would be worthwhile.

--bsiegel

but then, it would be real file format, which would make no sense since you already have options of 7zip AES and zip AES.

Not knowing contents of archives is actually beneficial when sending files over the net, since then an attacker has less information about encrypted files (which an big deal in some security reports on zip aes implementation).

If this means nothing to you, then you can simply use 7zip or zip's aes directly? You simply have both options in PowerArchiver as it stands right now.

[davidsplash]

it would be nice if we could have pae but with 7zip and zip aes inside it. better security.

[TBGBe]

Originally Posted by davidsplash

it would be nice if we could have pae but with 7zip and zip aes inside it. better security.

You can
Have to use two steps (of course).