4/29    How does data cracking work?  I guess someone intercepts some encoded
        data, and then try to apply many different conversions on the data to
        find the right conversion that yields the original data.  But then how
        does he know which conversion is the right one when he doesn't even
        know what the original data is?  -- newbie
        \_ Related question:  What were the problem(s) with SSH1?
           -- not-so-newbie
           \_ iirc, SSHv1 used the same dh key for both encryption and
              hmac w/o deriving separate keys for each.
        \_ Depends on application--some apps use poor randomness, insufficient
           keylength, static keys, re-used keys, etc.  Cracking can be done
           a couple of ways, including pattern analysis and just plain brute
           forcing--you're pretty unlikely to get, say, two different clear
           text tcp streams that both look "right".  Very often you're also
           not "cracking" anything, but rather relying on a buffer overflow or
           similar (as with the SSH CRC32 exploit.)  -John
        \_ What John said. Also, the TLA agencies do things like pattern
           and traffic analysis to try and look for information in the
           bitstream. A surprising amount of information can be figured
           just by looking at things like the frequency of certain
           sequences.
           \- hola, i do not know what "data cracking" means however, based
              on the followup comments, you may want to look at I GOLDBERG's
              [UCB] PhD thesis on the design of the "anonymized IP wormhole"
              which 1. presents a useful framework to think about "the problem
              space" 2. has an interesting discussion on confounding "generic
              traffic analysis". it may be more than you are looking for but
              isnt that long ... i image there is a shorter version of the
              "freedom" project [IG gaves some talks], but i dont know if
              there is something downloadable. --psb
              \- I note in passing IG uses the example of "you would never
                 expect the us govt and the libyan govt to collude!" which
                 is sort of funny given that MQ is now our good buddy.
                 is sort of funny given that MQ is now our good friend.
                 better add the north korean and syrian govts. the probabilty
                 of north korea becoming our friend = how many bits of crypto
                 strength? --psb