Secure Sockets Layer (SSL) is used in virtually every commercial web browser and server. In this book, one of the world's leading network security experts explains how SSL works -- and gives implementers step-by-step guidance and proven design patterns for building secure systems with SSL. Eric Rescorla also provides the first in-depth introduction to Transport Layer Security (TLS), the highly anticipated, maximum-security successor to SSL. Rescorla starts by introducing SSL's fundamentals: how it works, and the threats it is intended to address. One step at a time, he addresses each key SSL concept and technique, including cryptography, SSL performance optimization, designing and coding, and how to work around SSL's limitations. Rescorla demonstrates TLS at work in SMTP-based Internet security applications. The book includes detailed examples of SSL/TLS implementations, with in-depth insight into the key design choices that informed them. For all network and security designers, enterprise developers, system implementers, and suppliers of Internet security products and services.