This book offers an introduction to cryptology, the science that makes secure communications possible, and addresses its two complementary aspects: cryptography----the art of making secure building blocks----and cryptanalysis----the art of breaking them. The text describes some of the most important systems in detail, including AES, RSA, group-based and lattice-based cryptography, signatures, hash functions, random generation, and more, providing detailed underpinnings for most of them. With regard to cryptanalysis, it presents a number of basic tools such as the differential and linear...