Cryptography in C and C++ mainly focuses on the practical aspects involved in implementing public key cryptography methods, such as the RSA algorithm that was recently released from patent protection. It also gives both a technical overview and an implementation of the Rijndael algorithm that was selected as the Advanced Encryption Standard by the U.S. government. Welschenbach avoids complexities by explaining cryptography and its mathematical basis in terms a programmer can easily understand. This book offers a comprehensive, yet relentlessly practical overview of the fundamentals of modern cryptography. It includes a wide-ranging library of code in C and C++, including the RSA algorithm, completed by an extensive Test Suite that proves that the code works correctly. Readers will learn, step by step, how to implement a platform independent library for the all-important multi-precision arithmetic used in modern cryptography. This is followed by an implementation of the cryptographic algorithms themselves.