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So i've managed to answer all the other cryptography questions, but I have not come across this exam style question before, and need help.


migration rejected from security.stackexchange.com May 26 at 18:55

This question came from our site for Information security professionals. Votes, comments, and answers are locked due to the question being closed here, but it may be eligible for editing and reopening on the site where it originated.

closed as off-topic by e-sushi, rath, DrLecter, Gilles, Stephen Touset May 26 at 18:55

  • This question does not appear to be about cryptography within the scope defined in the help center.
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@Neelam, I'm having a hard time seeing what your question is. Are you just wanting one of us to answer i) and ii) for you or are you having trouble understanding the protocol? –  mikeazo May 22 at 11:57
Hint for i): Assume Trudy not knowing $K_A$ could impersonate as Alice to the NW with sizable probability, and prove Trudy could distinguish the cipher with unknown key $K_A$ from a random (permutation) oracle with sizable probability. Note for ii): IMHO the question is wrong and Eve does not even need to perform a man-in-the-middle attack, passive eavesdropping is enough. If you nevertheless want to answer the question as given, do the obvious: perform as NW vs Alice, and as Alice vs NW. –  fgrieu May 22 at 13:18
This question appears to be off-topic because it is about the style of the exam paper and not cryptography. –  rath May 25 at 10:49
Bleh. Posting a scan is lazy and rude. If you can't even be bothered to type a question, why should we be bothered to read it? And as for doing your homework, what have you tried? –  Gilles May 25 at 19:43