Security protocols are one of the most critical elements in enabling the secure communication and processing of information, ensuring its confidentiality, integrity, authenticity and availability. These protocols are vulnerable to a host of subtle attacks, so designing protocols to be impervious to such attacks has proved to be extremely challenging and error prone. This book provides a thorough and detailed understanding of one of the most effective approaches to the design and evaluation of security critical systems, describing the role of security protocols in distributed secure systems and the vulnerabilities to which they are prey. The authors introduce security protocols, the role they play and the cryptographic mechanisms they employ, and detail their role in security architectures, e-commerce, e-cash etc. Precise characterizations of key concepts in information security, such as confidentiality, authentication and integrity are introduced and a range of tools and techniques are described which will ensure that a protocol guarantees certain security services under appropriate assumptions. Modeling and Analysis of Security Protocols provides: An in-depth discussion of the nature and role of security protocols and their vulnerabilities. A rigorous framework in which security protocols and properties can be defined in detail. An understanding of the tools and techniques used to design and evaluate security protocols.