The tie, if I might suggest it, sir, a shade more tightly knotted. One aims at the perfect butterfly effect. If you will permit me " "What does it matter, Jeeves, at a time like this? Do you realize that Mr. Little's domestic happiness is hanging in the scale?" "There is no time, sir, at which ties do not matter." Cryptography: A concise survey of the cryptographic algorithms and protocols underlying network security applications, including encryption, hash functions, digital signatures, and key exchange Part Two Network Security Applications: Covers important network security tools and applications, including Kerberos, X.509v3 certificates, PGP, S/MIME, IP Security, SSL/TLS, SET, and SNMPv3 Part Three System Security: Looks at system-level security issues, including the threat of and countermeasures for intruders and viruses, and the use of firewalls and trusted systems. In addition, the book includes an extensive glossary, a list of frequently used acronyms, and a bibliography. Each chapter includes homework problems, review questions, a list of key words, suggestions for further reading, and recommended Web sites. A more detailed, chapter-by-chapter summary of each part appears at the beginning of that part. INTERNET SERVICES FOR INSTRUCTORS AND STUDENTS There is a Web page for this book that provides support for students and instructors. The page includes links to relevant sites, transparency masters of the figures and tables in the book in PDF (Adobe Acrobat) format, and sign-up information for the book's Internet mailing list. The Web page is at [A HREF="http://www.williamstallings.com/NetSec2e.html"> WilliamStallings.com/NetSec2e.html . An Internet mailing list has been set up so that instructors using this book can exchange information, suggestions, and questions with each other and with the author. As soon as typos or other errors are discovered, an errata list for this book will be available at WilliamStallings.com . In addition, the Computer Science Student Resource site, at WilliamStallings.com/StudentSupport.html , provides documents, information, and useful links for computer science students and professionals. PROJECTS FOR TEACHING NETWORK SECURITY For many instructors, an important component of a cryptography or security course is a project or set of projects by which the student gets hands-on experience to reinforce concepts from the text. This book provides an unparalleled degree of support for including a projects component in the course. The instructor's manual not only includes guidance on how to assign and structure the projects, but also includes a set of suggested projects that covers a broad range of topics from the text: Research Projects: A series of research assignments that instruct the student to research a particular topic on the Internet and write a report Programming Projects: A series of programming projects that cover a broad range of topics and that can be implemented in any suitable language on any platform Reading/Report Assignments: A list of papers in the literature, one for each chapter, that can be assigned for the student to read and then write a short report See Appendix B for details. RELATIONSHIP TO CRYPTOGRAPHY AND NETWORK SECURITY, THIRD EDITION This book is a spin-off from Cryptography and Network Security, Third Edition (CNS3e). CNS3e provides a substantial treatment of cryptography, including detailed analysis of algorithms and significant mathematical component, all of which covers almost 400 pages. Network Security Essentials: Applications and Standards (NSE2e) provides instead a concise overview of these topics in Chapters 2 and 3. NSE2e includes all of the remaining material of CNS3e. NSE2e also covers SNMP security, which is not covered in CNS3e. Thus, NSE2e is intended for college courses and professional readers where the interest is primarily in the application of network security, without the need or desire to delve deeply into cryptographic theory and principles.