1. How many DES encryptions take place in the ANSI X9.17 PRNG?
a) 3
b) 6
c) 9
d) 12
Explanation: Since there are 3 block, 12 DES encryptions take place.
2. How many keys are used in the ANSI X9.17 PRNG?
a) 3
b) 2
c) 4
d) 6
Explanation: 2 keys are used for the 3DES Encrypt Decrypt Encrypt method.
3. Which of the following PRNGs is used in most recent Intel Chips?
a) ANSI X9.17 PRNG
b) NIST CTR_DRBG
c) ANSI standard X9.82
d) None of the mentioned
Explanation: NIST CTR_DRBG is the PRNG used in most Intel Chips.
4. For the NIST CTR_DRBG , Seed length =
a) Output Block Length
b) Reseed Interval
c) Reseed Interval + Output Block Length
d) Output Block Length + Key Length
Explanation: Seed length = Output Block Length + Key Length
5. The CTR mode uses a Key K and an Initial Vector V. The Intel Digital Random Number generator has these values initially as
a) K = 0 ; V = 1
b) K = 0 ; V = 0
c) K = 1 ; V = 1
d) K = 1 ; V = 0
Explanation: K = 0 ; V = 0 for Intel Digital Random Number generator. (Initial Values)
6. What is the Seed length (seedlen) length for AES-192 ?
a) 428
b) 384
c) 320
d) 512
Explanation: Seed length = Output Block Length + Key Length = 128 + 192.
7. What is the Seed length (seedlen) length for 3DES?
a) 284
b) 260
c) 232
d) 216
Explanation: Seed length = Output Block Length + Key Length = 64 + 232.
8. With reference to stream ciphers, the output of the generator is called
a) Byte Stream
b) Re-Seed Interval
c) Key Length
d) Keystream
Explanation: The generator produces the Keystream.
9. Which of the following is not a valid design parameter to be considered in designing stream ciphers?
a) Keystream should be truly as random as possible
b) Encryption sequence should have a large value
c) Output of the PRNG (the key) should be sufficiently large
d) All of the mentioned are valid points that should be considered while designing stream cipher blocks
Explanation: a, b and c are all valid design parameters.
10. What is the maximum size of the key in blowfish algorithm?
a) 256 bits
b) 512 bits
c) 56 bytes
d) 48 bytes
Explanation: The maximum size of the key in blowfish algorithm is 56 bytes or 448 bits.