Bob and Kevin are both using crypto to communicate with other people. Bob doesn't want Kevin eavesdropping on his messages, and vice versa. They each need to choose algorithms and keys. Which of the following choices will protect one from eavesdropping by the other? Select all that apply.

A. Use the same algorithm and the same key.
B. Use different algorithms and the same key.
C. Use the same algorithm and different keys.
D. Use different algorithms and different keys.

Some of your friends have gotten into the burgeoning field of time-series data mining, in which one looks for patterns in sequences of events that occur over time. purchases at stock exchanges--what’s being bought-- are one source of data with a natural ordering in time. given a long sequence s of such events, your friends want an efficient way to detect certain "patterns" in them--for example, they may want to know if the four events buy yahoo, buy ebay, buy yahoo, buy oracle occur in this sequence s, in order but not necessarily consecutively. they begin with a collection of possible events (e. g., the possible’ transactions) and a sequence s of n of these events. a given event may occur multiple times in s (e. g., yahoo stock may be bought many times in a single sequence s). we will say that a sequence s’ is a subsequence of s if there is a way to delete certain of the events from s so that the remaining events, in order, are equal to the sequence s’. so, for example, the sequence of four events above is a subsequence of the sequence buy amazon, buy yahoo, buy ebay, buy yahoo, buy yahoo, buy oracle their goal is to be able to dream up short sequences and quickly detect whether they are subsequences of s. so this is the problem they pose to you: give an algorithm that takes two sequences of even~s--s’ of length m and s of length n, each possibly containing an event more than once--and decides in time o(m n) whether s’ is a subsequence of s

The head restraint should be adjusted so that it reaches a. the top of your ears b. the base of your skull c. the top of the head

Technician a says engine assemblies can be mounted longitudinally in a chassis. technician b says engine assemblies can be mounted transversely in a chassis. who is correct?