Computers in a LAN are configured to use a symmetric key cipher within the LAN to avoid hardware address spoofing. This means that each computer share a different key with every other computer in the LAN. If there are 100 computers in this LAN, each computer must have at least:

a. 100 cipher keys

b. 99 cipher keys

c. 4950 cipher keys

d. 100000 cipher keys

The correct answer is option (c) 4950 cipher keys

Explanation:

Solution

Given that:

From the given question we have that if there are 100 computers in a LAN, then each computer should have how many keys.

Now,

The number of computers available = 100

The number of keys used in symmetric key cipher for N parties is given as follows:

= N (N-1) / 2

= 100 * (100 - 1) / 2

= 50 * 99

= 4950 cipher keys