re ideas on clipper i was annoyed to find that this guy posted my private e mail response to him but since i believe what i said i ll defend it anyway in article gfpo wu wc qoq o andrew cmu edu jb m andrew cmu edu jon c r bennett writes jim gillogly jim mycroft rand org writes in private e mail they re betting that you can t cryptanalyze e to get u given n but we can t do this right now with des even knowing the encryption method without doing almost the whole bit search that is not true with chosen plaintext attacks des keys can be determined without the full search by almost i mean the differential cryptanalysis attack the chosen plaintext attack requires a detailed analysis of about chosen plaintexts drawn from a total of about that need to be run if i understand the situation correctly this is certainly a break under the meaning of the act but does not constitute much less work than the brute force keysearch the rest of his article assumes that we can figure out the skipjack encryption algorithm e by choosing the correct data to send through it and observe the results i wish him joy of it and choose not to try that attack i am not defending the system and in fact am offended by the ideas of escrowed keys or a secret algorithm becoming a de facto industry standard however i also object to opposing it for the wrong reasons since that weakens the case against it i said in my private e mail it s not clear that the experts will be told f in fact i d be surprised i d expect something more of the form of the fips pub describing des so that they could look at the algorithm in general rather than with the specific set of keys chosen oh come on thats like saying you could evaluate des without the s box constants no it s quite different the government would have no percentage in choosing f to be a weak key since it s not to their advantage to have anybody else know it the experts could thus assume that f is no worse than anything else during their analysis totally different situation from unknown s boxes again i m not saying it would be good or satisfactory for the experts to just be given the raw algorithm without the rest of the surrounding details regarding the chip and protocols and so on simply that i doubt that they would be given all the information jim gillogly trewesday thrimidge s r
