Cryptography Multiple Choice Questions on “Symmetric Key Distribution”.
1. If end to end connection is done at a network or IP level, and if there are N hosts, then what is the number of keys required?
a) N(N-1)/2
b) N
c) N(N+1)/2
d) N/2
Answer: a
Clarification: The number of keys required would be N(N-1)/2, similar to that of a mesh topology network connection (each node is connection line requires a key).
2. For 1000 nodes in IP level, how many keys would be required?
a) 499000
b) 499500
c) 500500
d) 500000
Answer: b
Clarification: Use N(N-1)/2 where N=1000.
3. Communication between end systems is encrypted using a key, often known as
a) temporary key
b) section key
c) line key
d) session key
Answer: d
Clarification: The key is referred to as session key.
4. Session keys are transmitted after being encrypted by
a) make-shift keys
b) temporary keys
c) master keys
d) section keys
Answer: c
Clarification: Each node has a master key which it uses to receive the session key.
5. For a network with N nodes, how many master keys are present?
a) N(N-1)/2
b) N
c) N(N+1)/2
d) N/2
Answer: b
Clarification: Each node has a master key to receive the session keys from the Key Distribution Centre (KDC).
6. PDU stands for
a) Protocol data unit
b) Pre data underscore
c) Permuted data unity
d) Protocol data untiy
Answer: a
Clarification: In key management, PDU stands for Protocol data unit.
7. SSM stands for
a) Secure Security Module
b) Session Security Module
c) Service Session Module
d) Session Service Module
Answer: b
Clarification: SSM stands for Session Security Module.
8. Which is the last step in establishing a connection between hosts using the SSM?
a) Interaction/ Handshaking between the SSM and the KDC
b) Establishment of the connection
c) Release of connection request packet
d) SSM saves the packet and applies to the KDC for connection permission
Answer: c
Clarification: The correct order of execution is – (d,b,a,c)