1- An important feature of any system is security. With a proper security measures implemented, attacks can be blocked. Define the terms security attack, security mechanism, and security service respectively with one example scenario.

2- In IPsec service, a security association is a one-way relationship between a sender and a receiver. The security association is identified by three parameters. Describe in detail IPsec SA and THREE (3) parameters.

3- advantages and disadvantages of static and dynamic

4- explain the security algorithm used in GSM