Jeff J. Stapleton is the author of Security without Obscurity: A Guide to Confidentiality, Authentication, and Integrity (CRC Press). Stapleton began his career at Citicorp Information Resources, St. Louis, Missouri, in 1982, as a software engineer writing 8-bit assembler code for a turnkey savings and loan teller system. He continued his work in the financial service industry at MasterCard International (St. Louis, Missouri), maintaining and developing credit card and debit card transaction applications on its global network, Banknet.

His introduction to cryptography began when he was assigned to develop a global key management system for MasterCard, and as part of that assignment, he began attending an Accredited Standards Committee (ASC) X9 Workgroup for retail banking security in 1989.

During his career, he has spoken at many conferences; participated in the development of numerous ANSI and ISO standards; and published various papers, articles, chapters, and his first bookSecurity without Obscurity.
W. Clay Epstein holds a bachelor of science in computer science from the University of Utah and a master of business administration in management information systems from Westminster College (Salt Lake City, Utah). He has international experience developing and managing public key infrastructures primarily for the financial services industry.

Epstein was the CTO for Digital Signature Trust Co., a start-up company formed to address the legal and technical issues of secure electronic commerce across the Internet, and one of the first licensed Certificate Authorities (CAs) in the United States. He was the third employee, responsible for the overall operations and strategic technology development, implementation, and maintenance of the various CA systems.