An Introduction to Mathematical Cryptography (Undergraduate Texts in Mathematics) Softcover reprint of hardcover 1st ed. 2008 Edition

At least for the chapters that were studied by this reviewer, the authors of this book give an effective introduction to the mathematical theory used in cryptography at a level that can be approached by an undergraduate senior in mathematics. The field of cryptography is vast of course, and a book of this size could not capture it effectively. The topics of primary importance are represented however, and the authors do a fine job of motivating and explaining the needed concepts.The authors give an elementary overview of elliptic curves over the complex numbers, and most importantly over finite fields whose characteristic is greater than 3. The case where the characteristic is equal to 2 is delegated to its own section. In discussing the arithmetic of elliptic curves over finite fields, the authors give a good motivation for Hasse's formula, which gives a bound for the number of points of the elliptic curve (over a finite field), but they do not go into the details of the proof. The Hasse formula is viewed in some texts as a "Riemann Hypothesis" for elliptic curves over finite fields, and was proven by Hasse in 1934. This reviewer has not studied Hasse's proof, but a contemporary proof relies on the Frobenius map and its separability, two notions that the authors do not apparently want to introduce at this level of book (however they do introduce the Frobenius map when discussing elliptic curves over F2). Separability is viewed in some texts in elliptic curves as more of a technical issue, which can be ignored at an elementary level. It arises when studying endomorphisms of elliptic curves of fields of non-zero characteristic, and involves defining rational functions. The Frobenius map is not separable, and this fact allows one to show that its degree is strictly greater than the number of points in its kernel. Taking the nth power of the Frobenius map and adding to it the endomorphism which simply multiplies elements by -1, one can show that the number of points of the elliptic curve is equal to the degree of this endomorphism. Just a few more arithmetical calculations establishes Hasse's estimate.Some more of the highlights of this part of the book: - The reminder that the fastest known algorithm to solve the elliptic curve discrete logarithm problem takes p^1/2 steps for a finite field Fp (i.e. the algorithms therefore are not really better than "black box" algorithms).- The brief historical discussion on public key cryptography.- The motivational discussion for the Lenstra algorithm using simple calculations that leads to a failed attempt to find the reciprocal of an integer modulo p. This failure is used to explain the workings of the Lenstra elliptic curve factorization algorithm in a way that it is better appreciated by the reader.- The discussion on the Frobenius map in the context of elliptic curves over F2 and its use in finding the number of points of an elliptic curve over a finite field.- The motivational discussion for the use of distortion maps, due to the degeneracy of the Weil pairing. The distortion maps are used to define a modified Weyl pairing, which is proved to be non-degenerate.Some omissions:- Algorithms used to calculate the number of points of an elliptic curve over a finite field that are more efficient than brute-force counting or estimation using Hasse's formula.- The proof that the torsion points of order m can be written as the product of two cyclic groups of order m. The authors apparently do not want to get into the notions of unramified and separable "isogenies" between elliptic curves and Galois extensions, both of which are used in the proof that they reference. Isogenies are mentioned in a footnote to the discussion on distortion maps, since the latter are isogenies.- The proof verifying certain properties of divisors, namely that they are equal if the corresponding rational functions are constant multiples of each other, and that the degree of a divisor is zero if its sum is the zero element of the elliptic curve. The proofs were no doubt omitted due to their dependence on techniques from algebraic geometry.- Quantum cryptography. This is discussed very briefly in the last chapter, but the subject is mature enough to be presented at the undergraduate level.- Cryptography based on non-Abelian groups. One good example would be cryptography based on the mathematical theory of knots and braids (the braid group is non-Abelian), even though this approach is in its infancy at the present time, and in almost all cases shown to be highly vulnerable to attacks. It could have been included in the last chapter or possibly as a long exercise.- Hyperelliptic curves are discussed very briefly in the last chapter, but a full-fledged presentation could be done in the book without missing the targeted audience. Hyperelliptic curves are also mentioned after the discussion of the MOV algorithm, wherein the authors allude to the use of Weil descent to transfer the elliptic curve discrete logarithm problem to a discrete logarithm problem in a finite field F2^m when m is composite. The authors correctly don't want to elaborate on Weil descent in any more detail, since it requires a solid knowledge of field extensions and theory of algebraic varieties at a level that one obtains in a graduate course in algebraic geometry. Suffice it to say that the strategy of Weil descent involves finding a cover of the elliptic curve by a hyperelliptic curve that is defined over the extension of the ground field. This approach has been shown to be problematic for Koblitz curves, the latter of which are discussed in the book.Note: This review is based on a reading of chapters 5 and 8 of the book.

The good: The writing is VERY good, with each concept presented cleanly and in a cheerful tone. Reading this book wasn't just informative. It was fun! I definitely plan to use it for my cryptography class next fall.The topics also proceed in a sensible order, both for self-study and for a class. It isn't an encyclopedia, covering all facts about modern cryptography. It's an undergraduate textbook, guiding you through the different areas of math that are related to modern cryptography and to each other, with enough real-world examples to keep your interest.All of the algorithms are explained carefully and then you're expected to actually use them in examples that are too big to do by hand (but are still small enough to easily crack with a computer). After a while, the fact that certain operations are easy and others are hard really sinks in.The bad: The level of sophistication expected of readers jumps up and down wildly, especially towards the back of the book. In the span of a few pages you might go from some subtle facts about algebraic geometry, stated without proof, back down to the definition of a vector space. If reading on your own, you probably will have to skip some of the harder stuff and will want to skim over the easy stuff. In a classroom, it's the instructor's job to provide that navigation.The good greatly outweighs the bad. 5 stars.

The book also has good exercises at the end of chapters.

Good start to this topic. The only hiccup was that I tried to work through the text example myself and came up with different answers. This is because the text was wrong. There is an extensive errata file that you can get online. May sure you get it before starting to work through text examples and end-of-chapter exercises. I hope that a revised version is issued that corrects these errata.

I picked up this book to review before I recommend it to my team of system engineers. Most of the textbooks I review are a mess and seem to exist solely to egrandize the author and subidize a professor's lifestyle.This book is a refreshing departure. The book is both readable and provides sufficient background to provide context to the reader.Highly recommended.

I'm doing my honor's thesis on theoretical Cryptography as an undergrad at Colby College, and this book has been the perfect resource. It is so clear, and many time teaches by using easy to understand concrete examples. This book is the perfect place to start if you want to learn about Crypto.

It is for undergrads, but useful at grad level to any student who didn't take the courses as an undergrad (i.e., fresh grad students discovering their love to cryptography)

It is a great book that gives the intro and mathematical background for an array of subjects and has allowed me to pick up the subject quite easily.

arrivato in buono stato. ottimo libro

The content of the book is very good, but the binding arrived damaged.

Good book for ug study or may be in first yest of pg