World Library  
Flag as Inappropriate
Email this Article


Article Id: WHEBN0000632592
Reproduction Date:

Title: Rc2  
Author: World Heritage Encyclopedia
Language: English
Subject: RC5, Cipher security summary, RC4, Cobra ciphers, FTPS
Collection: Broken Block Ciphers
Publisher: World Heritage Encyclopedia


The MIX transformation of RC2; four of these comprise a MIXING round
Designers Ron Rivest
First published leaked in 1996, designed in 1987
Cipher detail
Key sizes 8–1024 bits, in steps of 8 bits; default 64 bits
Block sizes 64 bits
Structure Source-heavy unbalanced Feistel network
Rounds 16 of type MIXING, 2 of type MASHING
Best public cryptanalysis
A related-key attack is possible requiring 234 chosen plaintexts (Kelsey et al., 1997).

In cryptography, RC2 (also known as ARC2) is a symmetric-key block cipher designed by Ron Rivest in 1987. "RC" stands for "Ron's Code" or "Rivest Cipher"; other ciphers designed by Rivest include RC4, RC5, and RC6.

The development of RC2 was sponsored by Lotus, who were seeking a custom cipher that, after evaluation by the NSA, could be exported as part of their Lotus Notes software. The NSA suggested a couple of changes, which Rivest incorporated. After further negotiations, the cipher was approved for export in 1989. Along with RC4, RC2 with a 40-bit key size was treated favourably under US export regulations for cryptography.

Initially, the details of the algorithm were kept secret — proprietary to RSA Security — but on 29 January 1996, source code for RC2 was anonymously posted to the Internet on the Usenet forum, sci.crypt. Mentions of CodeView and SoftICE (popular debuggers) suggest that it had been reverse engineered. A similar disclosure had occurred earlier with RC4.

In March 1998 Ron Rivest authored an RFC publicly describing RC2 himself.

RC2 is a 64-bit block cipher with a variable size key. Its 18 rounds are arranged as a source-heavy unbalanced Feistel network, with 16 rounds of one type (MIXING) punctuated by two rounds of another type (MASHING). A MIXING round consists of four applications of the MIX transformation, as shown in the diagram.

RC2 is vulnerable to a related-key attack using 234 chosen plaintexts (Kelsey et al., 1997).



External links

  • RFC 2268 - A Description of the RC2(r) Encryption Algorithm
  • RSA FAQ: What is RC2?
  • sci.crypt posting revealing the RC2 algorithm
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.

Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.