About Hans Rohrbach
Hans Rohrbach was a German mathematician. He worked both as an algebraist and a number theorist and later worked as cryptanalyst at Pers Z S, the German Foreign Office cipher bureau, during World War II. He was latterly known as the person who broke the American diplomatic O-2 cypher, a variant of the M-138-A strip cipher during 1943. Rohrbach wrote a report on the breaking of the strip cypher when he was captured by TICOM, the allied effort to roundup and seize captured German intelligence people and material. He submitted it and was awarded his doctorate on 25 July 1932. He was awarded the War Service Cross 2nd Class (KVK II) in September 1944, for his work on the solution of the U.S.
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