Shielding is material or a physical structure that blocks, redirects, or absorbs energy to reduce exposure. In electronics and security work, it often means metal enclosures, conductive mesh, or layered barriers that limit radiation, electromagnetic interference, or unwanted signals moving in or out of a device.
In cyber security, shielding matters because physical emissions can become information leaks. Proper shielding helps reduce side-channel exposure from electromagnetic leakage, protects sensitive hardware from external RF interference, and can support secure rooms or devices by making eavesdropping harder. It also appears in defense against malicious signal injection, where an attacker tries to disturb or control electronics through nearby radiation or strong fields. Good shielding is not a complete security control by itself, but it is an important layer that raises the cost and difficulty of both spying and interference.