Arcade machines employed multiple sophisticated strategies to prevent unauthorized copying and piracy of their games during the golden age of arcades. The primary protection method was through custom hardware. Game data was stored on read-only memory (ROM) chips specifically designed for proprietary circuit boards. These boards often featured unique architectures and security chips that would prevent the game from running if unauthorized components were detected.

The physical security of the cabinet itself served as another layer of protection. Machines were built with specialized locks and tamper-proof designs to prevent access to the internal components. Operators required specific tools and knowledge to access the game boards.

Many manufacturers implemented encryption and checksum verification systems. The game software would include code that verified the authenticity of the ROM contents during startup. If the checksum didn't match the expected value, the game would fail to boot or display error messages.

Legal and business measures complemented technical protections. Arcade operators entered into licensing agreements that prohibited copying games, and manufacturers maintained tight control over distribution. The specialized nature of arcade hardware also created natural barriers, as copied games would require identical hardware to function properly.

Some companies like Nintendo and Atari developed increasingly sophisticated protection methods throughout the 1980s, including custom microchips with encryption algorithms that were difficult to reverse engineer. While determined pirates eventually found ways around many protections, these measures successfully limited widespread piracy during the peak years of arcade gaming.