Jonathan K. Millen retired from his position as senior principal computer scientist in the cybersecurity division of The MITRE Corporation in 2012.

Jon obtained his PhD in mathematics from Rensselaer Polytechnic Institute in 1969; it came a year before RPI established a doctoral degree program in computer science. His initial programming experience was earlier, on Harvard’s UNIVAC II, writing binary machine language instructions on a form that was sent to punched-card machine typists. Working at The MITRE Corporation, in 1970, he was a member of a team that developed a COBOL program to produce Grade 2 Braille output for the MIT Sensory Aids Evaluation and Development Center. He has also used a Symbolics Lisp machine, acquired for MITRE artificial intelligence (AI) projects.

His work in computer security has involved various kinds of formal, symbolic analysis. It began with methods of information flow analysis to detect covert channels in operating system security kernels. These systems were being developed to satisfy government evaluation criteria for high-confidence multilevel security, as specified in the so-called Orange Book published by the National Computer Security Center in 1985. Jon was one of the authors of the subsequent Red Book for network security. During this period, he also developed a symbolic analysis tool to find security vulnerabilities in cryptographic key distribution protocols.

In 1988, Jon founded the Computer Security Foundations Workshop for the IEEE Computer Society. This workshop became the CSF Conference in 2008. He served terms as chair of the IEEE Technical Committee on Security and Privacy, and as general chair of its annual symposium. He cofounded the Journal of Computer Security, in 1991, and was co-editor-in-chief until retirement.

From 1997 to 2004, Jon worked at the SRI International Computer Science Laboratory as a senior computer scientist. It was there that he developed an improved protocol analyzer: the constraint solver. After returning to MITRE in 2004, he joined a team working on analysis of trusted platform modules. He was an editorial board member of ACM Transactions on Information and System Security from 1997 to 2006, and received an ACM SIGSAC Outstanding Innovation award in 2009.

Jon has been a reviewer for Computing Reviews since 1993.