According to the top lawyers of the NSA and FBI, their PRISM Internet program doesn’t search for keywords, but rather looks for dodgy email addresses and phone numbers. In other words, it doesn’t quite work the way you thought.

The authorities told the public hearing that the National Security Agency didn’t want to scoop up all online transmissions, but the surveillance was rather tailored to track or uncover terror suspects and other national threats. Talking about the NSA email spying, the attorneys said that the agency is “trying to figure out what it wants and gets that specifically”.

The Office of the Director of National Intelligence also claimed that it was targeted collection rather than bulk collection. But they seem to forget they are talking about PRISM – the program focused on foreign suspects outside the US. PRISM is subject to less virulent criticism than the other main clandestine operation disclosed by the agency’s ex-contractor Edward Snowden back in 2013, which was the NSA’s mass telephone metadata program collecting data on phone calls by most US citizens.

At the moment, the board is conducting a review of PRISM and other programs of the National Security Agency, which can draw “upstream” data directly off the Internet’s backbone.The agency argued that such programs are "compulsory legal" and that untargeted information is not stored.In the meantime, it is known that the default retention period for PRISM information collected from online companies is 5 years, and upstream data is kept for 2 years, according to the board.

The FBI lawyers told the board that the data collection from such web giants as Apple, Google and Microsoft is done with their knowledge.