imported>InternetArchiveBot：补救10个来源，并将0个来源标记为失效。) #IABot (v2.0.8

2021-02-08T16:51:27Z

补救10个来源，并将0个来源标记为失效。) #IABot (v2.0.8

新页面

{{noteTA
|G1=IT
}}
{{more footnotes|date=2009年3月}}
{{Infobox encryption method
| name = RC6
| image = [[Image:RC6 Cryptography Algorithm.JPG|300px|center]]
| caption = RC6算法的[[费斯妥密码|费斯妥函数]]。
| designers = [[罗纳德·李维斯特]]，[[Matt Robshaw]]，[[Ray Sidney]]，[[Yiqun Lisa Yin]]
| publish date = 1998
| derived from = [[RC5]]
| derived to =
| related to =
| certification = [[AES决赛算法]]
| key size = 128，192或256位
| block size = 128位
| structure = [[费斯妥密码]] (Type 2)<ref>{{cite conference |url=https://link.springer.com/chapter/10.1007%2F978-3-642-14623-7_33 |title=On Generalized Feistel Networks |last1=Hoang |first1=Viet Tung |last2=Rogaway |first2=Phillip |date=2010 |publisher=Springer |book-title=LNCS 6223 |pages=613-630 |location=USA |conference=CRYPTO 2010 |access-date=2018-09-27 |archive-date=2018-09-27 |archive-url=https://web.archive.org/web/20180927204226/https://link.springer.com/chapter/10.1007%2F978-3-642-14623-7_33 |dead-url=no }}</ref>
| rounds = 20
| cryptanalysis =
}}

在[[密码学]]中，'''RC6'''（'''Rivest cipher 6'''）是一个从[[RC5]]衍生而来的[[对称密钥加密|对称]][[分组密码|分组加密算法]]。它由[[罗纳德·李维斯特]]、[[Matt Robshaw]]、Ray Sidney以及 Ray Sidney设计，用以满足與[[高级加密标准]]（AES）[[高级加密标准评选过程|竞赛]]的要求。这个算法的是当时五个决赛候选算法之一，并且还提交给了[[NESSIE]]和[[CRYPTREC]]项目。这是一个专利算法，专利由[[RSA公司]]申请。

RC6拥有128位的[[块大小]]，支持128、192、256位乃至2040位的[[密钥长度]]。像[[RC5]]一样，RC6是可以被参数化的。它也因而支持变长的分组大小、密钥长度以及加密轮数。RC6和RC5在很多方面相似，例如结构、使用基于数据的置换规则、取模加法以及[[异或]]操作。事实上，RC6可以被看做是交织的两组平行的RC5加密。RC6使用了在RC5加密算法中并没有出现的乘法运算，这个运算是为了让置换基于[[字 (计算机)|字]]中每一位，而不是其中的几位。

== 加密和解密 ==
请注意，密钥扩展算法几乎是和RC5相同的。唯一的区别是，对于RC6来说，加密密钥中更多的字来自于用户提供的密钥。<syntaxhighlight lang="C">
// Encryption/Decryption with RC6-w/r/b
//
// Input: Plaintext stored in four w-bit input registers A, B, C & D
// r is the number of rounds
// w-bit round keys S[0, ... , 2r + 3]
//
// Output: Ciphertext stored in A, B, C, D
//
// '''Encryption Procedure:'''

B = B + S[0]
D = D + S[1]
for i = 1 to r do
{
t = (B*(2B + 1)) <<< lg w
u = (D*(2D + 1)) <<< lg w
A = ((A ⊕ t) <<< u) + S[2i]
C = ((C ⊕ u) <<< t) + S[2i + 1]
(A, B, C, D) = (B, C, D, A)
}
A = A + S[2r + 2]
C = C + S[2r + 3]

// '''Decryption Procedure:'''

C = C - S[2r + 3]
A = A - S[2r + 2]

for i = r downto 1 do
{
(A, B, C, D) = (D, A, B, C)
u = (D*(2D + 1)) <<< lg w
t = (B*(2B + 1)) <<< lg w
C = ((C - S[2i + 1]) >>> t) ⊕ u
A = ((A - S[2i]) >>> u) ⊕ t
}
D = D - S[1]
B = B - S[0]
</syntaxhighlight>

== NSA“植入”代码中可能使用了RC6 ==
2016年8月，一些被认为是来自[[方程式组织]]或[[美国国家安全局|国家安全局]]的代码被公开，这些代码"植入"了多种网络安全设备。<ref>{{cite news|url=https://arstechnica.com/security/2016/08/code-dumped-online-came-from-omnipotent-nsa-tied-hacking-group/|title=Confirmed: hacking tool leak came from “omnipotent” NSA-tied group|date=August 16, 2016|work=Ars Technica|accessdate=2018-09-27|archive-date=2017-06-06|archive-url=https://web.archive.org/web/20170606175632/https://arstechnica.com/security/2016/08/code-dumped-online-came-from-omnipotent-nsa-tied-hacking-group/|dead-url=no}}</ref>所附说明显示，这些程序使用了RC6以确保网络通信的机密性。<ref>{{cite web|url=https://github.com/nneonneo/eqgrp-free-file/blob/master/Firewall/BLATSTING/BLATSTING_20322/opinstructions/install.txt|title=These instructions guide the INSTALLATION of BLATSTING using ELIGIBLEBACHELOR via NOPEN tunnel.|accessdate=2016-08-16|archive-date=2019-02-17|archive-url=https://web.archive.org/web/20190217163523/https://github.com/nneonneo/eqgrp-free-file/blob/master/Firewall/BLATSTING/BLATSTING_20322/opinstructions/install.txt|dead-url=no}}</ref>

== 使用许可 ==
RC6没有被[[高级加密标准|AES]]选择，因为它不能保证RC6是免费的。{{As of|2017|1}}，来自RSA实验室的RC6的设计者们在他们的官方网站上声明：<ref>{{cite web|url=https://www.emc.com/emc-plus/rsa-labs/standards-initiatives/rc5-and-rc6.htm|title=3.6.4 What are RC5 and RC6?|accessdate=2015-08-02|publisher=[[RSA Laboratories]]|archive-date=2015-07-08|archive-url=https://web.archive.org/web/20150708061724/http://www.emc.com/emc-plus/rsa-labs/standards-initiatives/rc5-and-rc6.htm|dead-url=no}}</ref>

: "我们强调，''如果''RC6被选为AES，在产品中使用该算法，RSA公司将''不''要求任何许可证或授权费用"。

强调的词"如果"表明，RSA安全公司可能对任何使用了RC6的产品要求授权许可和支付授权费。RC6是一个专利加密算法([//www.google.com/patents/US5724428 美国专利5,724,428]，[//www.google.com/patents/US5835600 美国专利5,835,600])；但是，专利已经在2015年到2017年间过期。

== 注释 ==

* {{cite web
| url=http://people.csail.mit.edu/rivest/pubs/RRSY98.pdf
| title=The RC6 Block Cipher
| first1=R.L.
| last1=Pavan
| first2=M.J.B.
| last2=Robshaw
| first3=R.
| last3=Sidney
| first4=Y.L.
| last4=Yin.
| date=1998-08-20
| version=v1.1
| accessdate=2015-08-02
| archive-date=2015-10-10
| archive-url=https://web.archive.org/web/20151010114230/http://people.csail.mit.edu/rivest/pubs/RRSY98.pdf
| dead-url=no
}}

* {{cite web
| url=http://perso.ens-lyon.fr/jean-luc.beuchat/Publications/fpl2003.pdf
| title=FPGA Implementations of the RC6 Block Cipher
| first=Jean-Luc
| last=Beuchat
| archiveurl=https://web.archive.org/web/20060505225326/http://perso.ens-lyon.fr/jean-luc.beuchat/Publications/fpl2003.pdf
| archivedate=2006-05-05
| deadurl=yes
| accessdate=2018-09-27
}}

* {{cite web
| url=https://www.theregister.co.uk/2013/12/31/nsa_weapons_catalogue_promises_pwnage_at_the_speed_of_light/
| title=How the NSA hacks PCs, phones, routers, hard disks 'at speed of light': Spy tech catalog leaks
| first=Iain
| last=Thompson
| date=2013-12-31
| publisher=[[The Register]]
| accessdate=2015-08-02
| archive-date=2015-08-10
| archive-url=https://web.archive.org/web/20150810111740/http://www.theregister.co.uk/2013/12/31/nsa_weapons_catalogue_promises_pwnage_at_the_speed_of_light/
| dead-url=no
}}

== 参考资料 ==
{{reflist}}

== 外部链接 ==

* {{cite web
| url=http://embeddedsw.net/Cipher_Reference_Home.html#RC6
| title=Cryptography - 256 bit Ciphers: Reference source code and submissions to international cryptographic designs contests
| accessdate=2018-09-27
| archive-date=2011-09-26
| archive-url=https://web.archive.org/web/20110926210349/http://embeddedsw.net/Cipher_Reference_Home.html#RC6
| dead-url=no
}}

* {{cite web
| url=http://www.users.zetnet.co.uk/hopwood/crypto/scan/cs.html#RC6
| title=Symmetric Ciphers: RC6
| publisher=Standard Cryptographic Algorithm Naming (SCAN)
| date=2009-04-15
| accessdate=2018-09-27
| archive-date=2012-01-28
| archive-url=https://www.webcitation.org/652BeKiUl?url=http://www.users.zetnet.co.uk/hopwood/crypto/scan/cs.html#RC6
| dead-url=no
}}

* {{cite web
| url=https://www.emc.com/emc-plus/rsa-labs/historical/rc6-block-cipher.htm
| title=RC6® Block Cipher
| publisher=[[RSA Laboratories]]
| accessdate=2018-09-27
| archive-date=2016-03-04
| archive-url=https://web.archive.org/web/20160304055032/https://www.emc.com/emc-plus/rsa-labs/historical/rc6-block-cipher.htm
| dead-url=no
}}

{{Cryptography navbox | block}}

[[Category:分组密码]]

RC6 - 版本历史

imported>InternetArchiveBot：​补救10个来源，并将0个来源标记为失效。) #IABot (v2.0.8

imported>InternetArchiveBot：补救10个来源，并将0个来源标记为失效。) #IABot (v2.0.8