death_date death_place image_width birth_place significant_advance nationality name birth_date image article_title birth_name
12 november 1969 washington , d.c. 250px kishinev , bessarabia governorate cryptologist united states william f. friedman september 24 , 1891 william-friedman . jpg william f. friedman
 wolf friedman
william f. friedman

william frederick friedman -lrb- september 24 , 1891 -- november 12 , 1969 -rrb- was a us army cryptographer who ran the research division of the army 's signals intelligence service -lrb- sis -rrb- in the 1930s , and parts of its follow-on services into the 1950s .
in 1940 , subordinates of his led by frank rowlett broke japan 's purple cipher , thus disclosing japanese diplomatic secrets before america 's entrance into world war ii .
