Hill, Lester Sanders

(b. New York, N.Y., 19 January 1890; d. Bronxville, New York, 9 Hanuary 1961)

mathematics.

The son of James Edward Hill and the former Ellen Sheehan, Hill attended Columbia University, receiving the B.A. summa cum laude in 1911 and the M.A. in 1913. He taught mathematics at the University of Montana and at Princeton until 1916, when he joined the U.S. Naval Reserve. In 1921–1922 Hill was an associate professor of mathematics at the University of Maine; in 1922 he was appointed an instructor at Yale, where he was awarded the Ph.D. in 1926 with a dissertation entitled “Properties of Certain Aggregate Functions.” In 1927 Hill went to Hunter College in New York City, where he remained until his retirement except for 1945–1946, when he was a member of the faculty of the U.S. Army University at Biarritz, France.

Hill is probably best known for his mathematical approaches to cryptography and cryptanalysis, having been among the first to apply the theories and methods of matrices and linear transformations to the construction of secret codes. His work in this field, called the Hill system by A. A. Albert, was analyzed by Luigi Sacco in his Manuale di crittografia. Only after his death did the U.S. government reveal his associations with the code systems of the army, navy, and State Department during and after World War II. Most of his research in developing a modular algebraic cipher-code system is still unpublished and is classed as highly confidential material. It is described by H. C. Bruton, director, naval communications, as “ingenious, detailed, and complete.”

BIBLIOGRAPHY

I. Original Works. Hill’s published writings include “Concerning Huntington’s Continuum and Other Types of Serial Order,” in American Mathematical Monthly, 24 (1917), 345–348; “Cryptography in an Algebraic Alphabet,” ibid., 36 (1929), 306–312; “Concerning Certain Linear Transformation Apparatus of Cryptography,” ibid., 38 (1931), 135–154; “Probability Functions and Statistical Parameters,” ibid., 40 (1933), 505–532; “A Mathematical Checking System for Telegraphic Sequences,” in Telegraph and Telephone Age, 24 (October 1926); 25 (April 1927); 25 (July 1927); “Properties of Certain Aggregate Functions,” in American Journal of Mathematics, 49 (1937), 419–432, written with M.D. Darkow; and “An Algebraic Treatment of Geometry on a Spherical Surface,” in Scripta mathematica, 3 (1935), 234–246, 327–336.

II. Secondary Literature. See Luigi Sacco, Manuale di crittografia (Rome, 1936); New York Times (10 January 1961); New York Journal-American (10 January 1961); New York World-Telegram & Sun (10 January 1961); and Who’s who in the East (1959), 422.

Mary E. Williams