In this introductory textbook the author explains the key topics in cryptography. He takes a modern approach, where defining what is meant by "secure" is as important as creating something that achieves that goal, and security definitions are central to the discussion throughout. The chapters in Part 1 offer a brief introduction to the mathematical foundations: modular arithmetic, groups, finite fields, and probability; primality testing and factoring; discrete logarithms; elliptic curves; and lattices. Part 2 of the book shows how historical ciphers were broken, thus motivating the design of modern cryptosystems since the 1960s; this part also includes a chapter on information-theoretic security.

在这本介绍性教科书中，作者解释了密码学中的关键主题。他采用了一种现代方法，定义“安全”的含义与创建实现该目标的东西一样重要，而安全定义是整个讨论的核心。第1部分中的章节简要介绍了数学基础：模算术、群、有限域和概率；素性检验和因子分解；离散对数；椭圆曲线；和格子。这本书的第2部分展示了历史密码是如何被破解的，从而推动了20世纪60年代以来现代密码系统的设计；这一部分还包括一章关于信息理论安全的内容。