1. Explain why public key encryption is more useful for securing communications on the Internet than private (shared) key encryption.
2. As discussed in the chapter, string formatting could be used to simplify the dateconvert2.py program. Go back and redo this program making use of the string-formatting method.
3. A certain CS professor gives 5-point quizzes that are graded on the scale 5-A, 4-B, 3-C, 2-D, 1- F, 0-F. Write a program that accepts a quiz score as an input and prints out the corresponding grade.