Johannes Anton Marquart (born 27 September 1909 in Erolzheim in Germany)[1] was a German actuarial and insurance mathematician.
He eventually became head of Referat Ia of Group IV of the organization in November 1944[2] engaged in research into German Army hand cryptographic systems.
From 1940 to 1941, Marquart assisted Hans Pietsch, who was director of the mathematical cryptography department at In 7/VI, on hand ciphers, while working as a civilian.
Marquarts section achieved a fair measure of success with this system, owing to errors in encipherment, stereotyped signatures and also the fact that the cages were often filled up to rectangles with rare letters.
All cryptanalytic work on the double transposition systems was carried out entirely by hand by Marquart, and no attempt was made to develop any statistical machine methods for solution.
[4] All the counts which they made, however, failed to reveal any non-random characteristics in the design of the tables, and while they thought the Blocknots must have been generated by machine, they were never able to draw any concrete deductions as a result of their research.