Google has begun experimenting with encrypting Google Drive files, a privacy-protective move that could curb attempts by the U.S. and other governments to gain access to users’ stored files. Two sources told CNET that the Mountain View, Calif.-based company is actively testing encryption to armor files on its cloud-based file storage and synchronization service. One source who is familiar with the project said a small percentage of Google Drive files is currently encrypted. The move could differentiate Google from other Silicon Valley companies that have been the subject of ongoing scrutiny after classified National Security Agency slides revealed the existence of government computer software named PRISM. The utility collates data that the companies are required to provide under the Foreign Intelligence Surveillance Act — unless, crucially, it’s encrypted and the government doesn’t possess the key.