A hardware token is a small, removable physical device - such as a USB key or smart card - used to securely store authentication credentials. It provides an extra layer of security for accessing systems, networks, or applications by requiring the user to physically possess the device in addition to knowing a password or PIN. Hardware tokens are commonly used in two-factor or multi-factor authentication processes to prevent unauthorized access, as they are difficult to duplicate or steal remotely. These tokens may generate one-time passwords, store cryptographic keys, or facilitate secure login procedures, making them valuable for protecting sensitive data and systems.