Q11:

10 Bob offered Alice an X amount of money to complete a job. A hash value of the offer was calculate, the offer was digitally signed by Bob and sent to Alice. At pay time, Alice presented a request for the payment of $100, but Bod claimed that the offer was for $50. He presented a copy of the offer with a hashed value that confirms the $50, but Alice presented a different hash value that shows a $100 pay. How would you determine if Bob changed the offer and calculated a matching hash value or Alice change the offer, and calculated a matching hash value? * 11 In Demilitarized Zone(DMZ), an untrusted outside users can access DMZ but not the secure network, which provides additional security from external attacks, but does it prevent against internal attacks? If so, how does it add an additional layer of security to an organization's LAN. *