Unformatted text preview: With the help of a neat diagram describe signing using the publickey encryption where arbiter doesn’t see message. Explain how this protocol overcomes the alliances to defraud in the conventional encryption schemes. The solution can be found in the book. If you use the book, do not forget to make a reference to the book in your answer. Problem 6: Problem 13.9 from Stallings. Problem 7: (Optional) Suppose we use the ElGamal signature scheme with p=65539, α =2 and β =33384. Pablo wants to sign a message hi (809), and another, bye (22505). Note that the letters are coded as 01=a, 02=b, etc. The two signed messages (m,r,s) are: (809, 18357, 1042) and (22505, 18357, 26272). (a) Show that the same value of k was used for each signature. (b) Use this fact to Fnd this value of k and to Fnd the value of a such that β α a (mod p). 1...
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 Spring '09
 Algorithms, Cryptography, Publickey cryptography, Stallings, DifﬁeHellman keyexchange algorithm

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