Enigma was widely used, not just by Germany during the war, and was still current in the 50s. Additionally, the methods used to defeat Enigma had value against other encryption. It is also the policy of British intelligence not to publicise their work or capabilities.
British intelligence workers also took the Official Secrets Act at its word, while their American counterparts eventually assumed that as it was in the past they could talk about it.
Enigma was widely used, not just by Germany during the war, and was still current in the 50s. Additionally, the methods used to defeat Enigma had value against other encryption. It is also the policy of British intelligence not to publicise their work or capabilities.
British intelligence workers also took the Official Secrets Act at its word, while their American counterparts eventually assumed that as it was in the past they could talk about it.