Encryption for Folders

Question

Is there a directory-encryption variant similar to VIM's "vim -x file"? I am looking for something like "mkdir -encrypt folder".

Answer 1

TrueCrypt Its open source and supports multiple types of encryption.. What operating system do you wish to know about?

Edit: Windows Vista/XP, Mac OS X, and Linux are all supported.

Answer 2

There is no "general" way to encrypt directories (ie, one that works across all file and operating systems) (see below).

You can, however (as Dante mentioned) use TrueCrypt to create an encrypted filesystem in a file, then mount ("attach", in Windows terminology?) that file.

If you're using Linux, you can even mount that file at a particular directory, to make it appear that the directory is encrypted.

If you want to know how to use TrueCrypt, checkout the docs for Windows here: http://www.truecrypt.org/docs/?s=tutorial and for Linux here: http://www.howtoforge.com/truecrypt_data_encryption (scroll down to the "TrueCrypt Download" heading).

So, a quick explanation why you can encrypt files but not directories:
As far as the "computer" (that is, the hardware, operating system, filesystem drivers, etc) is considered, "files" are just "a bunch of bits on disk" (in the same way a book is "just a bunch of ink on paper"). When a program reads from or writes to a file, it can read or write whatever the heck it wants -- so if that program wants to encrypt some data before writing it to the file, or read a file then decrypt the data that it reads, great.

Directories are a different story, though: to read (ie, list) or write (ie, create) directories, the program (be it, mkdir, ls, Windows Explorer or Finder) has to ask the operating systeme, then the operating system asks the filesystem driver "Hey, can you make the directory /foo/bar?" or "hey, can you tell me what's in /bar/baz?" -- all the program or operating system see (basically) is a function to make directories and a function to list the contents of a directory.

So, to encrypt a directory, you can see that it would have to be the filesystem driver that is doing the encryption, not the program creating/listing the directories... And no modern filesystems support per-directory encryption.

Answer 3

On Linux, the simplest way is probably to use EncFS

"EncFS provides an encrypted filesystem in user-space. It runs without any special permissions and uses the FUSE library and Linux kernel module to provide the filesystem interface."

it basically mounts an encrypted folder as a plain one.

More info on wikipedia