Computer security pioneer, founder of Trusted Information Systems (TIS)
Bio at University of Maryland, Baltimore County (UBMC): http://ebiquity.umbc.edu/person/html/Steve/Walker/
TIS page at Wikipedia: https://en.wikipedia.org/wiki/Trusted_Information_Systems
Obituary: http://www.legacy.com/obituaries/baltimoresun/obituary.aspx?n=stephen-t-walker&pid=180600554&
Oral History at Babbage Institute: http://conservancy.umn.edu/handle/11299/144021