Question

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

I got this question in my homework.

This is a very interesting question from Symmetric Key Distribution topic in section Message Authentication Codes, Whirlpool Algorithm and Key Management and Distribution of Cryptograph & Network Security

Answer 1

Right option is (a) N(N-1)/2

For explanation I would say: 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).