Cryptography and Network Security: Principles and Practices, 6th Edition, by William Stalling,

Question 1:

Which parameters and design choices determine the actual algorithm of a Feistel cipher?

Question 2:

What is the difference between differential and linear cryptanalysis?

Question 3:

Review Question on page 125 of textbook

List three classes of polynomial arithmetic.

Question 4:

Does the set of residue classes modulo 3 form a group?

a. with respect to addition?

b. with respect to multiplication?

Question 5:

Find integers x such that:

a. 5x ≡4 (mod 3)

b. 7x≡6 (mod 5)

c. 9x ≡8 (mod 7)

Question 6:

In this text we assume that the modulus is a positive integer. But the definition of the expression a mod n also makes perfect sense if n is negative. Determine the following:

a. 5 mod 3

b. 5 mod -3

c. -5 mod 3

d. -5 mod -3

Question 7:

A modulus of 0 does not fit the definition, but is defined by convention as follows: a mod 0 = a. With this definition in mind, what does the following expression mean:

a ≡ b (mod 0)

Question 8:

Using the extended Euclidean algorithm, and find the multiplicative inverse of

a. 1234 mod 4321

b. 24140 mod 40902

c. 550 mod 1769

Question 9:

Develop a set of tables similar to Table 4.5 for GF(5).

Question 10:

Develop a set of tables similar to Table 4.7 for GF(4) with m(x) = x²+ x +1