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Locks were born almost simultaneously with private ownership. As early as 3000 BC, the Yangshao Cultural Site in China preserved wooden locks mounted on wooden framed buildings. At the time of the Eastern Han Dynasty, the technology of China's iron three-spring locks had a fairly high level. The three-spring lock has been used for more than 1,000 years. 1700s people invented by the British transfer sheet D. Porter cam locks. Its key number has grown from more than 20 of the three-spring locks to more than 80. In the mid-19th century, European manufacturers were converted into sliding rotor locks based on cam rotor locks and triple spring locks, with key numbers up to 1600. In 1848, American L. Yell invented the use of a cylindrical pin lock , which has become the most commonly used lock in the world. The structure of modern marble locks has new developments, including two-way, three-way, four-way marble structures, as well as flat, double-sided, multi-faceted, double-row double-sided, multi-row multi-faceted marble structures and combined marble structures, thereby greatly improving the lock. The security performance makes the number of the locks change from the original 2,500 kinds of "direction" and "face" to millions. In the 1970s, with the application of microelectronic technology, magnetic locks, voice locks, ultrasonic locks, infrared locks, electromagnetic wave locks, electronic card locks, gossip fingerprint locks, eyeball locks, and remote locks appeared. These locks have a high level of security that is unmatched by mechanical construction. Modern locks can also implement program control of the system in a specific system in a set logical relationship. Modern locks can be categorized by material, purpose, keyless, safety and structure.