Is there such a thing as cross-platform directory encryption (not disk encryption)?

[Eug]

I have a directory of work files that I want to encrypt on an exFAT external drive. Is it possible to do this and have it still work with both Windows and OS X? If it means installing an expensive 3rd party application (that may be defunct in 8 years or something), I'm not really interested.

Zip wouldn't work, since it's 17 GB.

 

[Fox5]

7zip or winrar can do this iirc.

I don't see why zip wouldn't work though. ZIP can be encrypted with AES, and I know at least 7-zip is able to do the encryption and decryption. I'm not sure it's a standard OS feature though, regular ZIP crypto is kind of weak but is another option.

Truecrypt is also still functional if you get an older version.

http://security.stackexchange.com/q...cryption-just-as-secure-as-truecrypts-version

 

[Eug]

Oh, OK. So, 17 GB isn't a problem them? There are a bazillion files in there. A LOT of the files are just a few hundred KB to a couple of MB.

How bad is the crypto with regular zip? This stuff isn't necessarily top secret, but I still want to make it non-trivial for people to access the information.

 

[Fox5]

Regular zip crypto is vulnerable to brute forcing, but it would require a dedicated effort to do so.
The AES zip crypto is supported by 7zip, winzip, winrar, and probably a few other tools. 17GB of files isn't a problem, and zip is a nice format because it can decompress the files individually. (so you don't have to decompress the entire 17GB worth of files)

You could also look at truecrypt for your purposes, which is available on windows, mac, and linux. It's unsupported now, but it still works.
https://www.grc.com/misc/truecrypt/truecrypt.htm