Question Five

1. There is a hashing algorithm called MD5. Find the difference between this algorithm

and SHA-l.

2. A message is made of 10 numbers between 00 and 99. A hash algorithm creates a

digest out of this message by adding all numbers modulo 100. The resulting digest

is a number between 00 and 99. Does this algorithm meet the first criterion of

a hash algorithm? Does it meet the second criterion? Does it meet the third criterion?

3. Answer all of the following:
   1. What is the purpose of a firewall?
   2. What are the two types of firewalls?
   3. What is a VPN and why is it needed?
   4. How do LANs on a fully private internet communicate?