ABSTRACT
This essay traces the efforts of American and German cryptanalysts to construct advanced code and cipher breaking machines before and during World War II. Extending the reach of the 1995 book, Information and Secrecy, this paper reveals that the Americans built more advanced machines than thought, such as the 5202 for the ‘Fish’ problem. However, that and their other machines usually emerged too late to meet the targeted crypto-crises – partly because of the failure to sustain a program of the mid-19308. The German program began much later and was much less productive than the American or British initiatives.
