bí mật thương mại pháp luật RC2 và RC4 được phát triển trong những năm 1980 bởi Ronald Rivest sử dụng RSA Data Security. Các thuật toán được thiết kế cực kỳ nhanh chóng và có thể điều hướng các thuật toán hỗ trợ các khóa mã hóa chiều dài thay đổi, | Securing Windows NT 2000 Servers for the Internet RC2 RC4 and trade secret law RC2 and RC4 were developed in the 1980s by Ronald Rivest for use by RSA Data Security. The algorithms were designed to be extremely fast and tunable the algorithms support variable-length encryption keys allowing keys as small as 1 bit or as long as 2048. Other than this fact and the fact that both are symmetric encryption algorithms the two algorithms have no similarity RC2 is a block cipher while RC4 is a stream cipher. Both names are trademarked by RSA Data Security. Unlike the RSA algorithm RC2 and RC4 were never patented. Instead the algorithms were kept as trade secrets protected by nondisclosure agreements and license agreements. Companies that had access to the RC2 and RC4 source code had to protect their trade secret measures and ensure that the code would not be revealed. Likewise any program in which the algorithm was embedded was accompanied by a license agreement forbidding disassembly of the program. Why keep an algorithm secret One reason that was given at the time was that the . Government thought that the RC2 and RC4 algorithms were too good to be put in general circulation perhaps the government had threatened RSA Data Security with some sort of retaliatory action in the event that the algorithms were publicly disclosed. Another reason suggested was that it was easier and cheaper to attempt to maintain the algorithms as a trade secret than to go through the exercise of patenting the algorithms in dozens of countries around the world and then attempting to police the technology. But regardless of what RSA Data Security s rationale was for keeping the algorithms as a trade secret the effort failed. A few years after the algorithms were put into widespread circulation they were both publicly revealed In 1994 the source code for a function claiming to implement the RC4 algorithm was anonymously published on the Internet. Although RSA Data Security at first .
