Vernam, Mauborgne, and Friedman: The One-Time Pad and the Index of Coincidence

Bellovin, Steven Michael

The conventional narrative for the invention of the AT and T one-time pad was related by David Kahn. Based on the evidence available in the AT and T patent files and from interviews and correspondence, he concluded that Gilbert Vernam came up with the need for randomness, while Joseph Mauborgne realized the need for a non-repeating key. Examination of other documents suggests a different narrative. It is most likely that Vernam came up with the need for non-repetition; Mauborgne, though, apparently contributed materially to the invention of the two-tape variant. Furthermore, there is reason to suspect that he suggested the need for randomness to Vernam. However, neither Mauborgne, Herbert Yardley, nor anyone at AT and T really understood the security advantages of the true one-time tape. Col. Parker Hitt may have; William Friedman definitely did. Finally, we show that Friedman's attacks on the two-tape variant likely led to his invention of the index of coincidence, arguably the single most important publication in the history of cryptanalysis.



More About This Work

Academic Units
Computer Science
Department of Computer Science, Columbia University
Columbia University Computer Science Technical Reports, CUCS-014-14
Published Here
June 17, 2014