Cryptography Multiple Choice Questions on “Whirlpool Algorithm”.
1. Which of the following is not true for whirlpool hashing function?
a) It is a two way hashing function
b) It is based on a 512 bit block cipher
c) The block cipher is similar to AES structure
d) It is resistant to differential attacks
Answer: a
Clarification: The whirlpool algorithm is a one way hashing algorithm.
2. The expected workload of generating a collision is of the order of ____________ executions of Whirlpool.
a) 2(n/2)
b) 2(n-1)
c) 2(n)
d) 2(2n)
Answer: a
Clarification: The expected workload of generating a collision is 2(n/2).
3. Given a message, the expected workload of finding a message that hashes to that value is of the order ____________
a) 2(n/2)
b) 2(n-1)
c) 2(n)
d) 2(2n)
Answer: c
Clarification: The expected workload would be 2n in such a case.
4. Given a message and its n-bit hash result, the expected workload of finding a message that hashes to the same value is of the order _______________
a) 2(n/2)
b) 2(n-1)
c) 2(n)
d) 2(2n)
Answer: c
Clarification: When the message and hash value are provided, the workload turns out to be 2n.
5. The message is padded to
a) 1024 bits
b) 512 bits
c) Odd multiple of 256 bits
d) Odd multiple of 512 bits
Answer: c
Clarification: The message in Whirlpool is padded to an odd multiple of 512 bits.
6. The length of the message is appended to the message. What is the size of this length?
a) 256 bits
b) 512 bits
c) 128 bits
d) 1024 bits
Answer: a
Clarification: The length is expressed as a 256 bit unsigned integer, with most significant byte being the leftmost.
7. The hash matrix is of the size
a) 16 × 8
b) 16 × 4
c) 8 × 8
d) 4 × 16
Answer: c
Clarification: The hash matrix has a 8 × 8 matrix.
8. The 8 × 8 hash matrix holds values of size
a) 16 bits
b) 32 bits
c) 8 bits
d) 4 bits
Answer: c
Clarification: 8 × 8 × 8 = 512 bits. 512 bits is the size of the message block. Thus we require 8 bits only.
9. The hash matrix of 8 × 8 is preferred over a 16 × 4 matrix because
a) it is symmetric
b) it is smaller in size
c) it is faster in computation
d) none of the mentioned
Answer: c
Clarification: 8 × 8 is preferred because it is faster.
10. How many rounds are there in one Whirlpool Iteration?
a) 3
b) 4
c) 6
d) 8
Answer: b
Clarification: There are 4 rounds in each Whirlpool step.
11. Which one of these is not a Whirlpool function?
a) Add Key
b) Substitute Bytes
c) Mix Rows
d) Shift Rows
Answer: d
Clarification: Shift columns is a valid operation. Rows are not shifted.