Read about the early history of the modern computer, particularly in the 30's and 40's. Learn about the leading figures including Claude Shannon, Alan Turing, John Von Neumann, and their links to military cryptanalysis. An excellent general source is Herman Goldstine's book [Goldstine, 1972]. Also, check out the biographies of Turing. A biography of one of these figures would be an interesting paper.
Another theme along these lines: Charles Babbage's cryptography. See [Babbage, 1994,Franksen, 1985] as well as several other sources in the library.