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?  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”.  Q.4. Explain how the DES algorithm can be strengthened by 3 DES. What is the effective key length of 3 DES? Justify.  Q.5. If a bit error occurs in the transmission of a ciphertext character in 8-bit CFB mode, how far does the error propagate?  Q.6. In a public-key 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?  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.  a. Permutation P b. Swapping of halves of the block ****** No. of Pages = 1 No. of Questions = 7...
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- Spring '11
- Cryptography, unconditionally secure cipher, computationally secure cipher, Exam Weightage Duration, Pilani Work-Integrated Learning