Communications security

Spies helped build Silicon Valley. Now the tables are turning

If you want to understand how modern British and American intelligence services operate, you could do worse than visit the new exhibition that opens at Bletchley Park this week. It tells the story of code-breaking in the first world war, which paved the way not just for the better-known success story of world war two, but also GCHQ and the NSA’s modern day bulk interception.