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Douglas Stinson. Cryptography: Theory and Practice.

CRC Press. 1995 . 434 pages. ISBN 0-8493-8521-0 $67.??

Bibliography (201 items). Index.

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Stinson's book is written from the perspective of applied discrete

mathematics, making it far more theory than practice, as acknowledged

in the preface. Coverage is based on "theoretical interest and

practical importance." This means if you have trouble with math beyond

algebra, this excellent textbook will be rough sledding for you. It is

not an introductory book on cryptography. If on the other hand, you

really want to know how the algorithms work and why, it is very useful.

Unlike some other textbooks, in this one Alice and Bob handle discrete

logarithms. There are lots of theorems, lemmas, proofs and formal

definitions.

He has divided the book into three main topics, private-key

cryptography, public-key cryptography and research in cryptography.

Each chapter has notes, references and exercises. While Stinson does

not claim completeness for his book, most things are covered to some

degree. DES, RSA, hashing and ElGamal get more attention, while

Kerberos gets only a brief description. MD4 and MD5 are just small

subsets of the hash chapter.

The first three chapters are dedicated to private-key cryptography,

with the requisite classical cryptography covered in the first. If you

were intrigued by Schneier's brief explanation of Shannon's perfect

secrecy, Stinson provides more detail in a complete chapter. His good

DES chapter is the last in the private-key section.

The largest topic is public-key cryptography, with six chapters devoted

to it. The relationship of the ElGamal cryptosystem and the discrete

logarithm problem is discussed along with several other associated

algorithms, for example, Shanks' algorithm and Pohlig-Hellman. The

chapter on identification schemes presents Schnorr's, Okamoto's, and

Guillou & Quisquater's.

The active areas of research covered in the last four chapters are

authentication codes, secret sharing schemes, pseudo-random number

generation and zero-knowledge proofs. Here, again, if Schneier has

piqued your interest in the Blum-Blum-Shub generator, a much more

detailed offering is available in Stinson.

I have put this book next to Schneier's on my bookshelf. I recommend

that if you are serious about cryptography, you should do the same.

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