Unformatted text preview: (e). What is Euler's totient function? Q.2. Which parameters and design choices determine the actual algorithm of a Feistel cipher? [5] Q.3. Construct a Playfair matrix with the key “ largest”. Using this matrix encrypt this message: “Must see you over Cadogan West. Coming at once”. [5] Q.4. Explain how the DES algorithm can be strengthened by 3 DES. What is the effective key length of 3 DES? Justify. [5] Q.5. If a bit error occurs in the transmission of a ciphertext character in 8bit CFB mode, how far does the error propagate? [5] Q.6. In a publickey system using RSA, you intercept the ciphertext C = 10 sent to a user whose public key is e = 5, n = 35. What is the plaintext M? [5] Q.7. Compare AES to DES. For each of the following elements of DES, indicate the comparable element in AES or explain why it is not needed in AES. [5] a. Permutation P b. Swapping of halves of the block ****** No. of Pages = 1 No. of Questions = 7...
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 Spring '11
 raj
 Cryptography, unconditionally secure cipher, computationally secure cipher, Exam Weightage Duration, Pilani WorkIntegrated Learning

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