Reflow soldering is the heating step used in surface-mount assembly to melt solder paste and create electrical and mechanical joints between components and a printed circuit board. The board is first coated with paste, parts are placed on the pads, and then controlled heat brings the solder above its melting point so it flows, wets the metal surfaces, and solidifies into reliable connections.
In cyber security, reflow soldering matters because hardware quality affects trustworthiness. Well-controlled reflow reduces open circuits, shorts, and intermittent faults that can hide in devices used for secure communications, access control, or embedded systems. Defenders and manufacturers use it to build and repair boards consistently, while attackers may rely on the same process when modifying hardware, replacing components, or assembling altered devices. Poor temperature profiles, bad stencils, or contaminated paste can leave weak joints that fail under stress and make boards easier to fingerprint or tamper with.