A government agency is designing a secure communication room where highly confidential conversations can take place without risk of electronic eavesdropping through radio frequency (RF) signals. Which of the following would most effectively ensure that RF signals cannot enter or leave the room?
Building the walls of the room with reinforced concrete
Installing a Faraday cage around the room
Soundproofing the room with acoustic foam
Using TEMPEST shielding for all computers and phones inside the room