This is a companion exercise and solution book to A Classical
Introduction to Cryptography: Applications for Communications Security
(0-387-25464-1). Coverage includes symmetric or public-key cryptography,
cryptographic protocols, design, cryptanalysis, and implementation of
cryptosystems. Readers should be comfortable with basic facts of
discrete probability theory, discrete mathematics, calculus, algebra,
and computer science. However, the exercises do not require an extensive
background in mathematics, since the most important notions are
introduced and discussed in many of them. Exercises related to the more
advanced parts of the textbook are marked with a star.