What should I do if I lose my BMW key? Will the information be leaked?

Use the spare key to drive the vehicle, and the information will not be leaked.

The key button of BMW consists of unlocking key, locking key, opening the trunk of the vehicle and finding the key, which has nothing to do with the information.

Both the master key and the slave key are lost. Use the password key to go to the 4S store to reconfigure. When buying a car, you need to take out the car purchase invoice, all bills, vehicle driving license and owner's certificate, and configure it in the 4S shop when buying a car.