2001: Claude Shannon, cryptologic pioneer, died.
Excerpt from Wikipedia:
Shannon was an American mathematician, electronic engineer, and cryptographer known as "the father of information theory".
Shannon is famous for having founded information theory with a landmark paper that he published in 1948. However, he is also credited with founding both digital computer and digital circuit design theory in 1937, when, as a 21-year-old master's degree student at the Massachusetts Institute of Technology (MIT), he wrote his thesis demonstrating that electrical applications of boolean algebra could construct and resolve any logical, numerical relationship. Shannon contributed to the field of cryptanalysis for national defense during World War II, including his basic work on codebreaking and secure telecommunications.