Antivirus giant Symantec is getting serious about encryption. The company announced Thursday that it's buying the encryption-focused firms PGP and Guardian Edge, paying $300 million for PGP and $70 million for the smaller firm. In a statement, Symantec emphasized that buying the two privately-held companies is part of its larger shift to "information-centric" security--a trend towards placing protections in data itself, no matter where it travels, rather than protecting the borders around that data with technology such as firewalls or antivirus software. That's become a higher priority as data more often resides on mobile devices or is distributed in off-site servers, sometimes controlled by a contractor or a storage-as-a-service company such as Google or Amazon.