Q. Which RC5 mode will have the ciphertext longer than the plaintext by at most the size of a single RC5 block?

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Q. Which one of the following is not a RC5 mode of operation?

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Q. “RC5 uses the Feistel Structure.”

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Q. RC5 encryption uses Right shift and decryption uses Left shift.

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Q. Calculate the number of subkeys required in RC5 for 18 rounds of computation.

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Q. The value of the golden ratio is

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Q. The value of the base of natural logarithms is

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Q. RC5 uses 2 magic constants to define their subkeys. These are

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Q. The total number of subkeys t used in the RC5 algorithm is given by the formula (r corresponds to number of rounds)

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Q. The standard/nominal version of the RC5-w/r/b has parameters w/r/b as

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Q. The number of rounds in RC5 can range from 0 to _____________

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Q. What are the allowable values of word size in bit for RC5 algorithm?

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Q. Which of the following is true for the RC5 algorithm?

i) Has variable number of rounds
ii) Has fixed Key length
iii) High memory Requirements
iv) Uses only primitive computational operations commonly found on microprocessors

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Q. Which of the following statements are true with respect to the blowfish algorithm –

i) Provided key is large enough, brute-force key search is not practical, especially given the high key schedule cost
ii) Key dependent S-boxes and sub keys make analysis very difficult
iii) Changing both halves in each round increases security
iv) Blowfish has improved avalanche effects

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Q. The 32bit output of s-box 1 is XORed with s-box 2.

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Q. A single blowfish s-box converts 8-bits to _________ bits.

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Q. What is the number of iterations required in total to generate all the sub-keys in blowfish?

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Q. P15 gets XORed with

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Q. P17 gets XORed with

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Q. To generate the sub-key P1 to P18 we use the hexadecimal equivalent digits of ____________

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