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In [[cryptography]], ”’RC2”’ (also known as ”’ARC2”’) is a [[Symmetric-key algorithm|symmetric-key]] [[block cipher]] designed by [[Ron Rivest]] in 1987. “RC” stands for “Ron’s Code”; other ciphers designed by Ron Rivest include [[RC4 (cipher)|RC4]], [[RC5]], and [[RC6]].
In [[cryptography]], ”’RC2”’ (also known as ”’ARC2”’) is a [[Symmetric-key algorithm|symmetric-key]] [[block cipher]] designed by [[Ron Rivest]] in 1987. “RC” stands for “Ron’s Code”; other ciphers designed by Ron Rivest include [[RC4 (cipher)|RC4]], [[RC5]], and [[RC6]].
The development of RC2 was sponsored by [[Lotus Software|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 few changes, which Rivest incorporated. After further negotiations, the cipher was approved for export in 1989. Along with RC4, RC2 with a [[40-bit encryption|40-bit]] [[key size]] was treated favourably under US [[Export of cryptography|export regulations for cryptography]].
The development of RC2 was sponsored by [[Lotus Software|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 few changes, which Rivest incorporated. After further negotiations, the cipher was approved for export in 1989. Along with RC4, RC2 with a [[40-bit encryption|40-bit]] [[key size]] was treated favourably under US [[Export of cryptography|export regulations for cryptography]].
Block cipher
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”[1] (see also RC2, RC5 and RC6), but generally it is simply called RC4.; other ciphers designed by Ron 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 few 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.[2]
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.
References
Bibliography
- Kelsey, John; Schneier, Bruce; Wagner, David (1997). “Related-key cryptanalysis of 3-WAY, Biham-DES, CAST, DES-X, NewDES, RC2, and TEA”. In Han, Y.; Okamoto, T.; Qing, S. (eds.). Information and Communications Security. Lecture Notes in Computer Science. Vol. 1334. Springer, Berlin, Heidelberg. pp. 233–246. doi:10.1007/BFb0028479. ISBN 978-3-540-63696-0. Retrieved 2018-10-10.
- Knudsen, Lars R.; Rijmen, Vincent; Rivest, Ronald L.; Robshaw, Matthew J. B. (1998-08-16). “On the Design and Security of RC2” (PDF). Fast Software Encryption. Lecture Notes in Computer Science. Vol. 1372. Springer Berlin Heidelberg. pp. 206–221. doi:10.1007/3-540-69710-1_14. ISBN 978-3-540-64265-7. Retrieved 2018-10-10.
- Levy, Steven (2001). Crypto : how the code rebels beat the government– saving privacy in the digital age. Penguin Books. ISBN 0-14-024432-8.
