US and British spy agencies have reportedly cracked the encryption codes that protect emails, bank accounts and medical records.
The BBC reports documents provided by Edward Snowden, a former US intelligence contractor who is now in Russia, were published on Friday by The Guardian newspaper and The New York Times.
The National Security Agency in the United States and the GCHQ in Britain are reported to have focused on the encryption used in 4G smartphones, email, online shopping and remote business communication networks.
These encryption techniques are used by internet services such as Google, Facebook and Yahoo.
The documents provided to The Guardian by Mr Snowden did not specify which companies participated.
The NSA is said to spend $US250 million per year on the operation.