The first edition of the "The Information Security Dictionary" defines over 1200 of the most commonly used words in the security field, with particular attention to those terms used most often in forensics, malware, viruses, vulnerabilities and IPv6. A new world of words has emerged from technology's affect on the language of our modern culture. "The Information Security Dictionary" is a reference tool that should become part of any IT professional and IT student's library, concisely formatted in one volume. Special attention is paid to terms which most often prevent educated readers from understanding journal articles and books in cryptology, security and information systems, and computer science, in addition to applied fields that build on these disciplines, such as system design, security auditing, vulnerability testing, and role-based access management. The emphasis throughout "The Information Security Dictionary" is on concepts, rather than implementations. Since concepts often complicate matters, readers may find a definition makes sense only after it has been illustrated by an example which the author provides in this dictionary.