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 been up to online.

In Britain, a report into the jihadi-inspired killing of a soldier in London said websites such as Facebook provide a “safe haven for terrorists” to communicate. Such statements echo similar concerns made in America. James Comey, the director of the FBI, has said the encryption of computers, smartphones and other digital gadgets largely benefits paedophiles, criminals and terrorists.