Suppose that this textbook was sold online (as a PDF) by your moneygrubbing author for, say, $5. Then the author would make more money off of each copy sold than he currently does10  and people who...

Suppose that this textbook was sold online (as a PDF) by your moneygrubbing author for, say, $5. Then the author would make more money off of each copy sold than he currently does10  and people who purchase the book would save a lot of money.

a. What are the security issues related to the sale of an online book?

b. How could you make the selling of an online book more secure, from the copyright holder's perspective?

c. How secure is your approach in part b? What are some possible attacks on your proposed system?