(b. 16 August 1905, Bydgoszcz; d. 13 February 1980, Warsaw)
Rejewski attended the Classical High School in Bydgoszcz from 1915 until 1923, when he passed the final examination. From 1923 to 1929 he studied mathematics at Poznań University. In March 1929, alongside Jerzy Różycki and Henryk Zygalski, he took part in (but did not complete) a secret course in the fundamentals of cryptology, organised by Poznań University and the Cipher Bureau of the Polish Armed Forces. In autumn 1929 he went to Göttingen for a year to study actuarial mathematics. After his return, he worked at Poznań University from 1931 to 1933, in the departments of theoretical physics (1931–1932) and mathematics (1932–1933). In September 1932 he was employed in the radio intelligence section of the General Staff of the Polish Armed Forces in Warsaw. In December 1932 he, Różycki and Zygalski became the first to break the code of the German Enigma encryption machine. He spent the war in France and Britain, continuing to work on the decryption of German ciphers. He returned to Poland in 1946, and took up work as an official in enterprises and industry unions in Bydgoszcz. He did not reveal his role in breaking the Enigma code until 1967, when he wrote his memoirs, which he deposited with the Military Historical Institute. He published 22 works. In 1979 he became an honorary member of the Polish Mathematical Society.
L. Maligranda, W. Wnuk, 100 lat matematyki na uniwersytecie w Poznaniu 1919–2019, Wyd. Nauk. UAM, Poznań 2021, pp. 352–364 and 489–490.