What is a Faraday cage in security?

D3 ยท Architecture  ยท  CompTIA Security+ SY0-701
A Faraday cage is a conductive enclosure that blocks electromagnetic fields (EMF) โ€” preventing radio waves, cellular signals, Wi-Fi, Bluetooth, and other wireless communications from entering or leaving the enclosed space.

Security uses:
๐Ÿ“ฑ Shielded rooms (SCIFs โ€” Sensitive Compartmented Information Facilities) for classified work
๐Ÿ”’ Evidence bags for seized devices (prevents remote wipe commands)
๐Ÿ’ณ RFID-blocking wallets (prevent card skimming)
๐Ÿญ Protecting ICS/SCADA from electromagnetic attacks
Faraday cages are used in digital forensics โ€” placing a seized phone in a Faraday bag prevents the owner from remotely wiping it before evidence can be extracted. SCIFs use Faraday shielding to prevent RF eavesdropping (TEMPEST protection). RFID-blocking wallets use the same principle.
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