This book covers public-key cryptography, describing in depth all major public-key cryptosystems in current use, including ElGamal, RSA, Elliptic Curve, and digital signature schemes. It explains the underlying mathematics needed to build these schemes, and examines the most common techniques used in attacking them. Illustrated with many examples, the book provides a solid foundation for professionals in government, cloud service providers, and large enterprises using public-key systems to secure their data. It is also useful for those taking the CISSP exam (Certified Information Systems Security Professional).