Problem
a) Both hashing and encryption produce a series of random numbers and letters. Are both concepts the same or different? How are they different in terms of the purposes? Data security involves confidentiality, integrity, authentication, non-repudiation, accountability. How are both techniques to do with these five goals? Why blockhead needs both techniques?
b) Discuss how and why Security, Scalability and Decentralization are three contradictory goals in blockchain world (trilemma)?