In weak offline implementations, the validation algorithm is entirely self-contained within the client application. Attackers use disassemblers and debuggers to locate the validation function. Once the algorithm is understood, a keygen is programmed to replicate the mathematical logic, producing keys that the software accepts as valid.

Modern commercial software typically utilizes one of two licensing verification methods:

The creation and distribution of keygens constitute violations of the Digital Millennium Copyright Act (DMCA) in the United States and similar international treaties. These laws prohibit the circumvention of technological measures that control access to copyrighted works.

While the intent of a user may be simply to use the software, the act of bypassing licensing undermines the economic model supporting software development. For specialized utilities like mobile unlock tools, which require continuous updates to keep pace with operating system security patches, the loss of revenue due to piracy can halt development, rendering the tool obsolete for new iOS or Android versions.