Also known as ARC2
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" (see also RC2, RC5 and RC6), but generally called simply RC2. Other ciphers designed by Ron Rivest include RC4, RC5, and RC6.
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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" (see also RC2, RC5 and RC6), but generally called simply RC2. 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.
RC2 source code
groups.google.com →Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable. / To commemorate the 1996 RSA Data Security Conference, the following code is released into the public domain by its author. Prost! This cipher uses 16-bit words and little-endian byte ordering. I wonder which processor it was optimized for? Thanks to CodeView, SoftIce, and D86 for helping bring this code to the public. / iQCVAwUBMQ1hEdNcQg4O6q8hAQE4rgP+Jx3+WaBETDVgeANS+6OObLFYN35pNJO8 cl732KR5rv1HSNjjFXfHx73JFcxQC7V+wrhqFNsUtrBMyrQk1PWN+Chjb4Kf+GR6 Wz9PBGW66xWi/UC87SUAfw7+VCKxbcFZFedhwB+746FJoXRv6PHMFCNFaYuIiKzY QcGbjnXqQcA= =yJNf END PGP SIGNATURE -- : "Just an eccentric soul with a curiosity for the bizarre." Has anyone managed to try this out with some known RC2 to see if they match? Don't know. It's not obviously a lousy algorithm, which says something. It is similar in design to MD2, which is a rumor I have heard. Rivest has said nothing; RSADSI has said nothing. Does anyone have a legal copy of the BSAFE toolkit who can try to decrypt messages encrypted with this thing? Bruce Schneier APPLIED CRYPTOGRAPHY, 2nd EDITION is Counterpane Systems available. For info on a 15% [email protected] discount offer, send me e-mail. Stephen Kapp wrote: Has anyone managed to try this out with some known RC2 to see if they match? According to people I have spoken to, RSADSI has all but admitted it is real. They are preparing another letter threatening legal action against anyone using what was once their trade secret. You'd think they would have had a letter already prepared after RC4. This was interesting. Is this another "S1," or another "alleged-RC4?" The whole thing looks pretty believeable, i.e., it doesn't have any obviously dumb parts that I can see. Note that alleged RC2's block encryption function looks an awful lot like one round of MD5 performed on 16-bit sub-blocks, using the bitwise selection function as the nonlinear function, and a key-derived constant table. Additionally, in rounds four and eleven, there are four lookups into the expanded key array. for(i=0;i / To commemorate the 1996 RSA Data Security Conference, the following code is released into the public domain by its author. Prost! This cipher uses 16-bit words and little-endian byte ordering. I wonder which processor it was optimized for? Thanks to CodeView, SoftIce, and D86 for helping bring this code to the public. / I heard that RC4 was also mentioned at the conference. Did they finally acknowledge the released code? Robert Salesas, Eschalon Development Inc. Visit our web site at www.eschalon.com According to people I have spoken to, RSADSI has all but admitted it is real. They are preparing another letter threatening legal action against anyone using what was once their trade secret. Given that the code was (going from the origin and the comments in it) reverse-engineered in Europe, and that reverse-engineering is legal in Europe and has been upheld by the Supreme Court in the US, do they have any basis for threatening someone? Based on the debate which followed the RC4 release I would have thought that RC2 is effectively in the public domain now. I think that that is for the courts to decide. All the legal advice I have heard says that RSADSI got screwed and you can do what you want with RC4. I know RSADSI has said things to people who were planning on using it though. It's really a matter of how brave you are and if you are willing to play ball if they don't like what you're doing. They might not be able to sue you or stop you from using it but they can make your life difficult, it is probably just easier for most people to switch to some other cipher. Given that the code was (going from the origin and the comments in it) reverse-engineered in Europe, and that reverse-engineering is legal in Europe and has been upheld by the Supreme Court in the US, do they have any basis for threatening someone? Based on the debate which follow
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Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).