This is the outline of a talk I gave at the rump session of Financial Cryptography 1997 conference. While I believe obscurity can be useful, I also feel there are few people able to properly evaluate its use and benefits. Risk of bad publicity Security Dynamics Plagued for years by rumors that could not be dispelled while their protocol was secret. It turns out the most rumored attacks about the value of breaking the chips were inaccurate. Mondex Unable to respond to claims that DFA would smash their system effectively, since obscurity forced them to speak in generalities.
Few people break protocols.
Many published ones go for years without problems being found. Few people can objectively weigh the risks of obscurity. The author in question clearly can. Allows analysis by outsiders No need to know which unbroken block cipher is in use for most attacks. Results in a more accurate estimate of time to break obscurity.