Please answer the following and provide a sentence explanation for each response.

1. Which of the following can be enforced in hardware?

a. Information flow

b. Memory safety

c. Type safety

d. All of the above

2. Which of the following are challenges to achieving complete mediation? (check all that apply).

a. A system administrator might have added a backdoor

b. Software has bugs

c. Security mechanisms are too powerful

d. Difficult to enforce the right security policy

3. Which of the following statements are true?

a. Optimizing code with undefined behavior away is a compiler bug, and compilers shouldn't do it

b. Introducing undefined behavior in a C program is a programming error, and the programmer should be blamed

c. All C compilers are identical in the way they optimize away code with undefined behavior

4. Which of the following statements are true about the guard model (check all that apply)?

a. In the guard model, the users are inside of the wall and trusted

b. The authentication module decides who is allowed to perform a request

c. A request is authentic when the guard can establish who the sender of the request is and that the message hasn't been modified by an adversary

d. The log allows an administrator to determine later which requests have been approved and which ones have been rejected

5. The semantics of a language is:

a. A set of principles that guide the design of a programming language

b. A set of rules that define how any program written in the language will behave

c. The set of constructs that make up a programming language

d. A way to avoid security vulnerabilities in a language