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 &times; 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> &ndash; 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]]