WASHINGTON — The government is quietly funding research to prevent eavesdroppers from seeing whom the U.S. is spying on.

The Associated Press has learned that the Office of the Director of National Intelligence has paid five research teams across the country to develop a system for high-volume, encrypted searches of electronic records kept outside the government's possession. The project is among several ideas that could allow the government to store Americans' phone records with phone companies or a third-party organization, but still search them as needed.

Under the research, U.S. data mining would be shielded by secret coding that could conceal identifying details from outsiders and even the owners of the targeted databases. That's according to government documents and AP interviews with researchers, corporate executives and government officials.