4. (10 points) Computer B requires a user name and a password for every login. User A needs to log on over the Internet. One solution (eg., telnet) is to send in A's user name and password to B in clear text. .What is the security vulnerability of this solution if there is any? Answer in 2 sentences or less. (5 points) .Design a better solution. Draw a diagram only to describe the message exchanges between A and B, and the content of each message. (5 points)