This chapter is designed to discuss hardware hacking. Hardware hacking is defined as modifying hardware appliances or electronic products to perform functions for which they were not originally intended. This could range from a simple software replacement to a complicated electrical circuit attack. Any piece of electronic equipment can serve as a candidate for hardware hacking. Particularly of interest are Personal Digital Assistants (PDAs), mobile telephones, and hardware authentication devices such as dongles, token cards, biometric devices, and smart cards. Other common targets are any devices that are network-enabled and have embedded cryptographic functionality, such as routers, switches, virtual private networks (VPNs), and cryptographic accelerators. Hardware hacking is done for the following reasons—general analysis of the product to determine common security weaknesses and attacks, access to the internal circuitry without evidence of device tampering, retrieval of any internal or secret data components, cloning of the device, retrieving memory contents, and elevation of privilege. Hardware hacking requires a physical set of tools. This chapter covers the background and process of hardware hacking, tools and other resources, and a few real-world examples. It chapter focuses on hacking electronic hardware devices to gain a security advantage.