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Cryptography help

  1. Jul 8, 2008 #1
    Hi I have stuck at these two exercises ...


    Suppose we use the Rabbin protocol and we have chosen p=31,q=51 and B=15. If we want to transmit the message M=20 which will be the encrypted message C?? Also what are the messages the recipient will receive decrypting C ??


    Suppose we work in RSA and Alice has the public key (n,e)=(667,3). Suppose m1=26, m2=46, and the signature of Alice in m1 is sig(m1). We want to find sig(m2). We have the right to give her a message x, x different from m2 and she will sign it. We can't use the factoring of 667 neither can we find the d from e=3. What message should we give her???

    thnx alot
  2. jcsd
  3. Jul 8, 2008 #2

    was this assigned as a homework problem in a class?

    just curious.

  4. Jul 9, 2008 #3
    no I am just trying to solve them from a book I study these days..
  5. Jul 9, 2008 #4

    What's the name of the book?

  6. Jul 9, 2008 #5
    Introduction to Cryptography by Johannes Buchmann
  7. Jul 9, 2008 #6
    I'll see if I have a copy. DJ
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