Cryptography Questions and Answers – Overview – III

This set of Cryptography Multiple Choice Questions & Answers (MCQs) focuses on “Overview – 3”

1. The number of rounds in RC5 can range from 0 to _____________
a) 127
b) 63
c) 255
d) 31
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2. Multiply the polynomials P1 = (x⁵ + x² + x) by P2 = (x⁷ + x⁴ + x³ + x² + x) in GF(28) with irreducible polynomial (x⁸ + x⁴ + x³ + x + 1). The result is
a) x⁴+ x³+ x+1
b) x⁵+ x³+ x²+x+1
c) x⁵+ x⁴+ x³+x+1
d) x⁵+ x³+ x²+x
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3. RC5 uses 2 magic constants to define their subkeys. These are
a) Base of natural Logarithm and Golden ratio
b) Base of natural Logarithm and Pi
c) Golden Ratio and Pi
d) Pi and Golden Ration
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4. How many keys are used in the ANSI X9.17 PRNG?
a) 3
b) 2
c) 4
d) 6
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5. The GCD of x⁵+ x⁴+ x³– x² – x + 1 and x³ + x²+ x + 1 over GF(3) is
a) 1
b) x
c) x + 1
d) x² + 1
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6. The property that any extracted subsequence should pass the test for randomness is
a) Scalability
b) Uniformity
c) Stability
d) Consistency
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7. Maurer’s Universal Statistical Test is
a) a test to determine whether the number of runs of ones and zeros of various lengths is as expecte
b) a test to detect if a sequence can be significantly compressed without loss of information
c) a test to determine whether the number of ones and zeros in a sequence is approx the same as in a truely random o/p
d) a test for the check of evenness in the 1s and 0s
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8. Find the first 8 bits for Blum Blum Shub Bit Generator when seed = 101355 and n = 192649.
a) 10101010
b) 11100010
c) 11001011
d) 11001110
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9. Which one of the following is not a RC5 mode of operation?
a) RC5 block cipher
b) RC5-Cipher Block Chaining
c) RC5-Cipher Padding
d) RC5-CipherText Stealing
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10. On Encrypting “thepepsiisintherefrigerator” using Vignere Cipher System using the keyword “HUMOR” we get cipher text
a) abqdnwewuwjphfvrrtrfznsdokvl
b) abqdvmwuwjphfvvyyrfznydokvl
c) tbqyrvmwuwjphfvvyyrfznydokvl
d) baiuvmwuwjphfoeiyrfznydokvl
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11. Consider the cipher text message:
YJIHX RVHKK KSKHK IQQEV IFLRK QUZVA EVFYZ RVFBX UKGBP KYVVB QTAJK TGBQO ISGHU CWIKX QUXIH DUGIU LMWKG CHXJV WEKIH HEHGR EXXSF DMIIL UPSLW UPSLW AJKTR WTOWP IVXBW NPTGW EKBYU SBQWS

Relative Frequencies
3 7 2 2 5 5 7 9 11 4 14 4 2 1 3 4 6 5 6 5 7 10 9 8 4 2

The Index of Coincidence is
a) 0.065
b) 0.048
c) 0.067
d) 0.044
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12. The plain text for the cipher text RRLMWBKASPDH. Given the encryption key
[(17 17 5 | 21 18 21 | 2 2 19)] is –
a) PAYMOREMONEY
b) PAYINGRANSOM
c) GETINTHECAB
d) THEEXPRESSID
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13. The Inverse S-box value for byte stored in cell (D,2)
a) 0x5F
b) 0x2D
c) 0x7F
d) 0x5D
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14. Division of (131B6C3) base 16 by (lA2F) base 16 yeilds
a) 1AD
b) DAD
c) BAD
d) 9AD
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15. How many rounds does the AES-192 perform?
a) 10
b) 12
c) 14
d) 16
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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.

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