__NOTOC__ eCryptfs (''Enterprise Cryptographic Filesystem'') is a package of

disk encryption software Disk encryption software is computer security software that protects the confidentiality of data stored on computer media (e.g., a hard disk, floppy disk, or USB device) by using disk encryption. Compared to access controls commonly enforced by a ...

for

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which ...

. Its implementation is a

POSIX The Portable Operating System Interface (POSIX) is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. POSIX defines both the system- and user-level application programming interf ...

-compliant filesystem-level

encryption In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can decip ...

layer, aiming to offer functionality similar to that of

GnuPG GNU Privacy Guard (GnuPG or GPG) is a free-software replacement for Symantec's PGP cryptographic software suite. The software is compliant with RFC 4880, the IETF standards-track specification of OpenPGP. Modern versions of PGP are interoperabl ...

at the

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also in ...

level, and has been part of the

Linux kernel The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU ope ...

since version 2.6.19. The eCryptfs package has been included in

Ubuntu Ubuntu ( ) is a Linux distribution based on Debian and composed mostly of free and open-source software. Ubuntu is officially released in three editions: ''Desktop'', ''Server'', and ''Core'' for Internet of things devices and robots. All the ...

since version 9.04 to implement Ubuntu's encrypted

home directory A home directory is a file system directory on a multi-user operating system containing files for a given user of the system. The specifics of the home directory (such as its name and location) are defined by the operating system involved; for ...

feature, but is now deprecated eCryptfs is derived from Erez Zadok's Cryptfs. It uses a variant of the

OpenPGP Pretty Good Privacy (PGP) is an encryption program that provides cryptographic privacy and authentication for data communication. PGP is used for signing, encrypting, and decrypting texts, e-mails, files, directories, and whole disk partitio ...

file format for encrypted data, extended to allow

random access Random access (more precisely and more generally called direct access) is the ability to access an arbitrary element of a sequence in equal time or any datum from a population of addressable elements roughly as easily and efficiently as any othe ...

, storing cryptographic

metadata Metadata is "data that provides information about other data", but not the content of the data, such as the text of a message or the image itself. There are many distinct types of metadata, including: * Descriptive metadata – the descriptive ...

(including a per-file randomly generated

session key A session key is a single-use symmetric key used for encrypting all messages in one communication session. A closely related term is content encryption key (CEK), traffic encryption key (TEK), or multicast key which refers to any key used for enc ...

) with each individual file. It also encrypts file and directory names which makes them internally longer (average one third). The reason is it needs to uuencode the encrypted names to eliminate unwanted characters in the resulting name. This lowers the maximum usable byte name length of the original file system entry depending on the used file system (this can lead to four times fewer characters for example for Asian utf-8 file names).

References

{{Reflist

External links

ArchWiki: System Encryption with eCryptfs

(Zadok et al., 1999) Cryptographic software Disk encryption

See also

References

External links