Hardware is the physical part of a device: the casing, chips, memory, sensors, ports, and other internal components that make a system run. In cyber security, hardware matters because security is not only about software. If an attacker can reach the device itself, they may be able to tamper with components, attach rogue peripherals, extract data from storage, or alter boot behavior before the operating system starts.
Hardware also shapes defenses. Secure boot, TPMs, hardware-backed encryption, and tamper-resistant designs help verify that a device starts in a trusted state and keeps secrets protected. In real attacks, hardware weaknesses often appear through supply-chain compromise, physical access, or modified components that are hard to detect with software tools alone. For defenders, understanding hardware means knowing what is inside the device, how it connects, and where physical control can become a security failure.