Twitter's new encryption could prevent governments from snooping on old tweets

Internet services can toughen their security to mitigate government surveillance, but that won't do much to lock down information that's already in snoops' hands. Twitter hopes to prevent those raids on past data through its recent implementation of Perfect Forward Secrecy, an encryption technique that stops intruders from decoding traffic on a grand scale. Each communication session has a random encryption key that never travels across networks; even if spies get full access to Twitter's archives, they'll have to crack any PFS-protected chats one at a time. The new policy won't stop determined government agents from reading your tweets, but it will make them work harder for anything they want.