eCryptfs is a cryptographic stacked Linux filesystem. eCryptfs stores cryptographic metadata in the header of each file written, so that encrypted files can be copied between hosts; the file will be decrypted with the proper key in the Linux kernel keyring. There is no need to keep track of any additional information aside from what is already in the encrypted file itself. You may think of eCryptfs as a sort of "gnupgfs", or "gnupg as a filesystem".

eCryptfs is widely used, as the basis for Ubuntu's Encrypted Home Directory, natively within Google's ChromeOS, and transparently embedded in several network attached storage (NAS) devices.

Originally authored by Michael Halcrow and the IBM LInux Technology Center, eCryptfs is derived from Erez Zadok's Cryptfs, and the FiST framework for stacked filesystems. eCryptfs extends Cryptfs to provide advanced key management and policy features. eCryptfs is currently actively maintained by Dustin Kirkland (of Gazzang, Inc) and Tyler Hicks (of Canonical, Ltd).

The eCryptfs home page is:
 * http://ecryptfs.org

The mailing list for users and developers is:
 * http://vger.kernel.org/vger-lists.html#ecryptfs

The ecryptfs-utils userspace code is stored in Launchpad/Bazaar, and can be obtained with:
 * https://code.launchpad.net/~ecryptfs/ecryptfs/trunk

The ecryptfs kernel code is stored in Git/Kernel.org, and can be obtained with:
 * https://git.kernel.org/?p=linux/kernel/git/tyhicks/ecryptfs.git;a=summary

The Google+ page is:
 * https://plus.google.com/103860974668504356550

StackExchange Questions and Answers:
 * http://stackexchange.com/filters/33360/ecryptfs