Answer Happy

3. . (a) Exemplify the vulnerabilities of smart contracts by naming two attack types that are related to arithmetic operations. (2 marks) (b) Describe any 4 smart contract attack types, distinguishing the pre- conditions and triggers for each type of attack. (8 marks) (c) Explain how it is possible to ensure that the smart contract is designed such that any vulnerabilities that may arise can be fixed at a later date despite the immutability of the blockchain. (2 marks) (d) Explain two fundamental reasons why a “Byzantine Fault” should ever exist. (4 marks) (e) Specify the design objective of a Byzantine Fault Tolerant System and the pre-condition for a system to be able to tolerate the Byzantine Fault problem. (4 marks)