1- which of the following is NOT true about a hash function?

A- it converts a message of fixed length to an arbitrary length value.

B- it coverts a message of arbitrary length into a value of fixed length.

C- Given the digest value, it should be computationally infeasible to find the original message.

D- it should be impossible or rare to derive the same digest from two different message .

2- which of the following OSI layers adds a trailer?

A- Network Layer

B- Layer 2

C- Layer 4

D- Data Layer

3- which of the following is a control and information protocol used by network devices to determine things like a remote network's availability and length of time to reach a remote network?

A- ICMP

B- UDP

C- NAT

D- TCP