A goal of systems engineer should be to eliminate all risks from a project.

For an added point (or partial credit), briefly describe why interphase was once called the “resting phase” of cell division, but is no longer called this.

If the key space has size , brute-force key search requires approximately:

[O] In the one-time pad, suppose the key is chosen uniformly at random but the message space is restricted to only English words. Does this violate perfect secrecy? Explain.

A pseudorandom generator must be:

A distinguisher for pseudorandomness must:

Which of the following encryption schemes cannot achieve perfect secrecy?

[S] The definition of indistinguishability in Definitions 3.8 (page 55), 3.18 (page 70), 3.21 (pages 73-74) and 3.22 (page 74) all follow the pattern: Pr[Adversary success] ≤ 1/2 + negl(n). Can we suggest that we could equivalently state these as: Pr[Adversary success] = 1/2 +negl(n) (where + denotes plus or minus). Discuss.

[O] The OFB mode is discussed in Figure 3.8 (Page 92). Explain the following statement: “In OFB mode, a bit flip in ci for i > 0 only causes a bit flip in message block mi. However, a bit flip in c0 (i.e., in IV) will result in all the plaintext blocks being recovered incorrectly.” What is the effect of bit flip in CTR mode?

[O] Suppose a function negl(n) satisfies: negl(n) = 2-n/2, is it considered negligible? Explain.