Key, lock core and lock

A lock core comprising:

• a body, provided with a lock hole, the lock hole being configured to be mated with a column body of a key;
• a photo sensor disposed at a bottom of the lock hole;
• a second cathode component disposed on an inner wall of the lock hole and configured to be mated with a first cathode component on the key;
• at least one second piezoelectric electrode having a polymer insulating layer disposed on a surface thereof, disposed on an inner wall of the lock hole, connected to the second cathode component, and configured to be pressed against a first piezoelectric electrode on the key;
• wherein, when the second cathode component is mated with the first cathode component in the lock core, and the second piezoelectric electrode is pressed against the first piezoelectric electrode of the key, a closed circuit is formed and a piezoelectric current is generated, to drive the light emitting component of the key to emit light, the light signal is received by the photo sensor and converted to a control signal to be output to the lock for controlling the locking and unlocking of the lock.