DES algorithms
The first algorithm presented in this chapter is Data Encryption Standard (DES). Its history began in 1973 when the National Bureau of Standards (NBS), which later became the National Institute of Standards and Technology (NIST), required an algorithm to adopt as a national standard. In 1974, IBM proposed Lucifer, a symmetric algorithm that was forwarded from NIST to the National Security Agency (NSA). After analysis and some modifications, it was renamed DES. In 1977, DES was adopted as a national standard and it was largely used in electronic commerce environments, such as in the financial field, for data encryption.
Remarkable debates arose over the robustness of DES within the academic and professional community of cryptologists. The criticism derived from the short key length and the perplexity that, after a review advanced by the NSA, the algorithm could be subjected to a trapdoor, expressly injected by the NSA into DES to spy on encrypted communications.
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