Cryptography MCQ set number 00534

1. Which Authentication Encryption approach is taken by the SSL/TLS protocol?
a) Hashing followed by encryption (H→E)
b) Encryption followed by authentication (E→A)
c) Authentication followed by encryption (A→E)
d) Independently encrypt and authenticate (E + A)

Answer

Answer: c [Reason:] Authentication followed by encryption (A→E) is the AE approach taken by the SSL/TLS protocol.

2. Which Authentication Encryption approach is taken by the IPSec protocol?
a) Authentication followed by encryption (A→E)
b) Hashing followed by encryption (H→E)
c) Encryption followed by authentication (E→A)
d) Independently encrypt and authenticate (E + A)

Answer

Answer: c [Reason:] Encryption followed by authentication (E→A) is the AE approach taken by the IPSec protocol.

3. Which Authentication Encryption approach is taken by the SSH protocol?
a) Hashing followed by encryption (H→E)
b) Encryption followed by authentication (E→A)
c) Authentication followed by encryption (A→E)
d) Independently encrypt and authenticate (E + A)

Answer

Answer: d [Reason:] Independently encrypt and authenticate (E + A)is the AE approach taken by the SSH protocol.

4. Hashing followed by encryption (H→E) is used by which algorithm?
a) IPSec
b) SSH
c) WEP
d) SSL/TLS

Answer

Answer: c [Reason:] WEP uses Hashing followed by encryption (H→E) algorithm.

5. Which of the following terms is not an input to the CCM encryption?
a) Nonce.
b) Associated data.
c) Plaintext message.
d) Tag.

Answer

Answer: d [Reason:] A tag is not involved with CCM.

6. How many passes through the plaintext does the CCM require to generate the MAC value?
a) 2
b) 3
c) 4
d) 5

Answer

Answer: a [Reason:] The CCM requires 2 passes through the plaintext to generate the MAC value.

7.
What does the following figure represent?
a) GCM (Galois Counter MAC)
b) GCTR ( part of GCM)
c) GHASH ( hash algorithm of GCM)
d) None of the mentioned

Answer

Answer: c [Reason:] The figure is the hash producing function of the Galois Counter MAC.

8. In GCM, we define S as S = GHASH(A||0^v||C||0^u||[len(A)]||[len(C)]). What is u defined as?
a) 64 ceil[len(A)/128] – len(A)
b) 64 ceil[len(C)/128] – len(C)
c) 128 ceil[len(A)/128] – len(A)
d) 128 ceil[len(C)/128] – len(C)

Answer

Answer: d [Reason:] u = 128 ceil[len(C)/128] – len(C).