Includes bibliographical references and index.

Email and security background -- Understanding email -- Security fundamentals -- Cryptography primer -- PKI basics -- Understanding public key infrastructure -- Secure email -- Protecting email message contents -- Protecting email passwords, headers, and commands -- Tokens and hardware security modules -- Case studies -- Signatures and authentication for everyone -- Department of Defense public key infrastructure, medium grade service, and common access card -- National Institute of Standards and Technology personal identity verification -- Expectations for the future -- Future developments -- ABNF primer -- ASN.1 primer -- MIME primer -- RFC summaries.