Arnold Dumey

Arnold I. Dumey was the co-inventor of the postal sorting machine and cryptanalyst first for ASA and then NSA. Dumey was also the inventor of Hashing. He published the first hashing paperDumey , A. I. (1956). "Indexing for rapid random-access memory". Computers and Automation 5 (12), 6-9] in 1956 while at IBM, where he co-invented the postal sorter. The "Dumey microsecond" is a term of art in the intelligence community of the United States where Dumey spent much of his career. The Dumey Microsecond was a crucial event that Arnold claimed was common to all projects: It is that microsecond during which you can impact the flow of, or design of, a project. Before this microsecond, it is too early. After, it is too late to have an impact.

Dumey was the longest serving member in the history of the NSA scientific advisor board. James Bamford, "Puzzle Palace", Chapter 9]

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