Digital privacy: Cryptography for dummies

A CAMPAIGN by American and British lawmakers and security officials to get social-media companies to take more responsibility for handing over information about criminals and terrorists using their networks gathered pace this week. It is happening because, following the documents leaked by Edward Snowden, a former American spy, technology companies are beefing up the encryption of data to protect users' privacy, making it more difficult for law-enforcement agencies to find out what people have b...