Homework 0 (extra credit)
			  due Thursday, Jan. 15

These are exercises at the end of Chapter 1 of the text, along with hints.
You may also wish to look at the notes on RSA encryption that I provide
from the course home page, http://www.ccs.neu.edu/course/csu690/ .

1.22  Easy if you recall the "definition of inverse modulo N" --
	x^{-1} mod N satisfies:  x x^{-1} mod N = 1
1.23  Prove it by assuming that there are two inverses: a1^{-1} and a2^{-2}
	and show that it leads to a contradiction.
1.24  Harder problem.  Consider different cases, when the
	element has no prime factor p, when it has one prime factor p,
	when it has two prime factors p, etc. 
1.45 (part a and b only:  For part b, only implement pseudo-code)

Comment (not assigned):
	  There is a paper that describes how to play Poker on the
          telephone by using other ideas from public-key cryptography.
	  For those who are interested, here is a description:
		http://www.murky.org/blg/poker-by-phone/