Comment by tptacek
6 hours ago
What do you mean? For as long as I remember (back to late 1994) people understood DES to be inadequate; we used DES-EDE and IDEA (and later RC4) instead. What "secrecy" would there have been? The feasibility of breaking DES given a plausible budget goes all the way back to the late 1970s. The first prize given for demonstrating a DES break was only $10,000.
Triple-key DES (DES-EDE) had already been proposed by IBM in 1979, in response to the criticism that the 56-bit keys of DES are far too short.
So practically immediately after DES was standardized, people realized that NSA had crippled it by limiting the key length to 56 bits, and they started to use workarounds.
Before introducing RC2 and RC4 in 1987, Ronald Rivest had used since 1984 another method of extending the key length of DES, named DESX, which was cheaper than DES-EDE as it used a single block cipher function invocation. However, like also RC4, DESX was kept as a RSA trade secret, until it was leaked, also like RC4, during the mid nineties.
IDEA (1992, after a preliminary version was published in 1991) was the first block cipher function that was more secure than DES and which was also publicly described.
People were willing to explicitly explain why it was inadequate rather than keep it secret. That is the difference.
What was to explain? It had a 56-bit key.
Was that the only thing wrong with it? The 90s was definitely before my time but I was under the impression reading about it that there were also fundamental flaws with DES which lead to the competition which ultimately produced AES.
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