Symmetric Ciphers Questions and Answers – Blowfish Algorithm – II

This set of Cryptography Multiple Choice Questions & Answers (MCQs) focuses on “Blowfish Algorithm”.

1. In blowfish, the keys are stored in the form of an array ranging from K1, K2 to Ki. What is the value of i?
a) 12
b) 16
c) 8
d) 14
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2. To generate the sub-key P1 to P18 we use the hexadecimal equivalent digits of ____________
a) 0.7864
b) 0.1415
c) 0.1542
d) 0.7535
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3. P17 gets XORed with
a) K3
b) K12
c) K17
d) K6
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4. P15 gets XORed with
a) K3
b) K14
c) K1
d) K6
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5. What is the number of iterations required in total to generate all the sub-keys in blowfish?
a) 512
b) 521
c) 256
d) 128
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6. A single blowfish s-box converts 8-bits to _________ bits.
a) 32
b) 44
c) 56
d) 64
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Answer: a
Explanation: The blowfish round algorithm –

7. The 32bit output of s-box 1 is XORed with s-box 2.
a) True
b) False
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8. 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

a) i) ii) and iv)
b) ii) and iii)
c) i)
d) All are true
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Sanfoundry Global Education & Learning Series – Cryptography and Network Security.

To practice all areas of Cryptography and Network Security, here is complete set of 1000+ Multiple Choice Questions and Answers