SEED
1063358
215044792
2008-05-26T13:25:18Z
Thumperward
545027
unsourced and dubious given the Windows-centricity of the protocol
{{otheruses|seed}}
{{Infobox block cipher
| name = SEED
| designers = [[Korean Information Security Agency|KISA]]
| publish date = 1998
| derived from =
| derived to =
| related to =
| key size = 128 bits
| block size = 128 bits
| structure = Nested [[Feistel network]]
| rounds = 16
| cryptanalysis =
}}
'''SEED''' is a [[block cipher]] developed by the [[Korean Information Security Agency]]. It is used broadly throughout [[South Korea]]n industry, but seldom found elsewhere. It gained popularity in Korea because 40 bit SSL was not considered strong enough (see [[Transport Layer Security#Early short keys]]), so the Korean Information Security Agency developed its own standard. However, this decision has limited the competition of [[web browser]]s in Korea, as no major SSL libraries or web browsers currently support the SEED algorithm, and users are limited to using [[ActiveX]] components with [[Internet Explorer]] for secure web sites.<ref>{{cite web |author=Gen Kanai |date=2007-01-26 |title=The Cost of Monoculture |url=http://www.kanai.net/weblog/archive/2007/01/26/00h53m55s#003095 |accessdate=2007-01-29 }}</ref>
SEED is a 16-round [[Feistel network]] with [[block size (cryptography)|128-bit blocks]] and a [[key size|128-bit key]]. It uses two 8 × 8 [[S-box]]es which, like those of [[SAFER]], are derived from discrete [[exponentiation]] (in this case, x<sup>247</sup> and x<sup>251</sup> – 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 function]]s such that each output bit depends on 3 of the 4 input bytes.
SEED has a fairly complex [[key schedule]], 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 [[Tiny Encryption Algorithm|TEA]]) from the [[Golden ratio]].
==References==
{{refs}}
==External links==
*[http://www.kisa.or.kr/seed/seed_eng.html SEED introduction] (English)
*[http://www.kanai.net/weblog/archive/2007/01/26/00h53m55s Blog about SEED in Korea]
*[http://webstandard.or.kr/en/2007/03/17/korean-home-brew-on-the-web/ Explanation of how ActiveX controls are used in conjunction with SEED for Korean e-commerce]
* [http://www.kisa.or.kr/seed/data/Document_pdf/SEED_Specification_english.pdf SEED official specification document] (English)
* RFC 4269: The SEED encryption algorithm (obsoletes RFC 4009)
* RFC 4010: Use of the SEED Encryption Algorithm in Cryptographic Message Syntax (CMS)
* RFC 4196: The SEED Cipher Algorithm and Its Use with IPsec
{{crypto-stub}}
{{Crypto navbox | block}}
[[Category:Block ciphers]]
[[de:SEED (Algorithmus)]]
[[fr:SEED]]
[[ja:SEED_(暗号)]]
[[ko:SEED]]