Product activation is a license validation procedure required by some proprietary computer software programs. In one form, product activation refers to a method invented by Ric Richardson and patented (US 5,490,216) by Uniloc where a software application hashes hardware serial numbers and an ID number specific to the product's license (a product key) to generate a unique installation ID. This installation ID is sent to the manufacturer to verify the authenticity of the product key and to ensure that the product key is not being used for multiple installations.