1. What is the maximum size of the key in blowfish algorithm?
a) 256 bits
b) 512 bits
c) 56 bytes
d) 48 bytes
Answer
Answer: c [Reason:] The maximum size of the key in blowfish algorithm is 56 bytes or 448 bits.
2. Blowfish encrypts blocks of plaintext which have size
a) 256 bits
b) 64 bits
c) 72 bits
d) 128 bits
Answer
Answer: c [Reason:] The size of the blocks of the plaintext is 64 bits each.
3. The blowfish algorithm can be implemented on 16 bit processors.
a) True
b) False
Answer
Answer: b) [Reason:] The statement is false as 32/64 bit processors are only capable of encrypting/decrypting the blowfish algorithm.
4. What is the minimum size of the key in blowfish algorithm?
a) 64 bits
b) 32 bits
c) 56 bits
d) 48 bits
Answer
Answer: b [Reason:] The minimum size of the key in blowfish algorithm is 4 bytes or 32 bits.
5. The blowfish algorithm’s key expansion converts a key of at most 448 bits into several subkey arrays totaling ___________ bytes.
a) 4096
b) 4608
c) 4168
d) 4864
Answer
Answer: c [Reason:] Key expansion converts a key of at most 448 bits into several sub key arrays totaling 4168 bytes i.e. eighteen 32-bit sub keys + four 8×32-bit s boxes = 4168.
6. Blowfish algorithm uses the Feistel Structure.
a) True
b) False
Answer
Answer: a [Reason:] In the blowfish algorithm data encryption occurs via a 16-round Feistel network.
7. XOR and addition operations take place on bytes of size
a) 8 bits
b) 16 bits
c) 32 bits
d) 64 bits
Answer
Answer: c [Reason:] XOR and addition operations take place on bytes of size 32 bits.
8. How many S-boxes are present in the blowfish algorithm?
a) 2
b) 4
c) 6
d) 8
Answer
Answer: b [Reason:] There are 4 s-boxes in the blowfish algorithm.
9. How many entries are present in each of the S-boxes present in the blowfish algorithm?
a) 256
b) 512
c) 1024
d) 64
Answer
Answer: a [Reason:] There are 4 s-boxes with 256 entries each in the blowfish algorithm.
