generate cryptography keys, see Key generator.
A software license is a legal instrument that governs the usage and distribution of computer software. Often, such licenses are enforced by implementing in the software a product activation or digital rights management (DRM) mechanism seeking to prevent unauthorized use of the software by issuing a code sequence that must be entered into the application when prompted or stored in its configuration.
Keygens are available for download on various websites dedicated to bypassing of product registration and activation, or to software piracy in general. In most countries, the use of keygens to activate software without purchasing a license is fraudulent. Keygen software distributions can be infected with malware by third parties, although this isn't always the case with most scene releases, as some keygens that are infected by unscrupulous third parties are often considered to be nuked releases.