After the war, Bletchley’s... «The Code Book: The Science of Secrecy from Ancient Egypt to Quantum Cryptography»

After the war, Bletchley’s accomplishments remained a closely guarded secret. Having successfully deciphered messages during the war, Britain wanted to continue its intelligence operations, and was reluctant to divulge its capabilities. In fact, Britain had captured thousands of Enigma machines, and distributed them among its former colonies, who believed that the cipher was as secure as it had seemed to the Germans. The British did nothing to disabuse them of this belief, and routinely deciphered their secret communications in the years that followed.