SEED is a
block cipher
In cryptography, a block cipher is a deterministic algorithm operating on fixed-length groups of bits, called ''blocks''. Block ciphers are specified cryptographic primitive, elementary components in the design of many cryptographic protocols and ...
developed by the
Korea Internet & Security Agency (KISA). It is used broadly throughout
South Korean industry, but seldom found elsewhere. It gained popularity in Korea because
40-bit encryption
40-bit encryption refers to a (now broken) key size of forty bits, or five bytes, for symmetric encryption; this represents a relatively low level of security. A forty bit length corresponds to a total of 240 possible keys. Although this is a larg ...
was not considered strong enough, so the Korea Information Security Agency developed its own standard. However, this decision has historically limited the competition of
web browsers in Korea, as no major SSL libraries or web browsers supported the SEED algorithm, requiring users to use an
ActiveX control in
Internet Explorer for secure web sites.
On April 1, 2015 the
Ministry of Science, ICT and Future Planning
The Ministry of Science, ICT and Future Planning (MSIP, ) was a ministry of the Government of South Korea. Its purpose is to set, manage, and evaluate science and technology policy, support scientific research and development, develop human resour ...
(MSIP) announced its plan to remove the ActiveX dependency from at least 90 percent of the country's top 100 websites by 2017. Instead,
HTML5-based technologies will be employed as they operate on many platforms, including mobile devices. Starting with the private sector, the ministry plans to expand this further to ultimately remove this dependency from public websites as well.
Design
SEED is a 16-round
Feistel network with
128-bit blocks and a
128-bit key. It uses two 8 × 8
S-boxes which, like those of
SAFER, are derived from discrete
exponentiation (in this case, x
247 and x
251 – plus some "incompatible operations"). It also has some resemblance to
MISTY1 in the recursiveness of its structure: the 128-bit full cipher is a Feistel network with an F-function operating on 64-bit halves, while the F-function itself is a Feistel network composed of a G-function operating on 32-bit halves. However the recursion does not extend further because the G-function is not a Feistel network. In the G-function, the 32-bit word is considered as four 8-bit bytes, each of which is passed through one or the other of the S-boxes, then combined in a moderately complex set of
boolean functions such that each output bit depends on 3 of the 4 input bytes.
SEED has a fairly complex
key schedule
In cryptography, the so-called product ciphers are a certain kind of cipher, where the (de-)ciphering of data is typically done as an iteration of ''rounds''. The setup for each round is generally the same, except for round-specific fixed valu ...
, generating its thirty-two 32-bit subkeys through application of its G-function on a series of rotations of the raw key, combined with round constants derived (as in
TEA) from the
Golden ratio.
Use and adoption
SEED has been adopted by several standard protocols:
S/MIME (RFC 4010),
TLS/SSL
Transport Layer Security (TLS) is a cryptographic protocol designed to provide communications security over a computer network. The protocol is widely used in applications such as email, instant messaging, and voice over IP, but its use in securi ...
(RFC 4162),
IPSec (RFC 4196), and ISO/IEC 18033-3:2010.
NSS software security library in Mozilla's Gecko platform has implemented support for SEED, and
Mozilla Firefox
Mozilla Firefox, or simply Firefox, is a free and open-source web browser developed by the Mozilla Foundation and its subsidiary, the Mozilla Corporation. It uses the Gecko rendering engine to display web pages, which implements current and a ...
as of 3.5.4 supports SEED as a TLS cipher; however, Mozilla decided to drop the support of SEED by default in Firefox 27 and above because support for SEED has not had any practical positive effect in terms of helping South Korea migrate away from ActiveX-based e-commerce, and other browsers are not offering any SEED-based cipher suites. NSS still supports SEED-based cipher suites.
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 ...
has supported SEED since 2007.
supports SEED in their full suite of data cryptography solutions.
References
External links
SEED - KISA(Official Site, in Korean)
SEED official specification document(English)
* : The SEED encryption algorithm (obsoletes )
* : Use of the SEED Encryption Algorithm in Cryptographic Message Syntax (CMS)
* : Addition of SEED Cipher Suites to Transport Layer Security (TLS)
* : The SEED Cipher Algorithm and Its Use with IPsec
{{DEFAULTSORT:Seed
Feistel ciphers
Internet in South Korea
Standards of South Korea