A security key system is embedded into most modern vehicle keys. A small chip rests on the vehicle’s key or under the plastic key cover. When any key is inserted into the ignition, the ignition is coded. The key sends its security code to the ignition, which also has its own security code, and if the security codes match, the vehicle will start when the key is turned. However, if the key codes don’t match, the vehicle won’t start when the key is turned. Some security keys can be programmed by the user, though most of these keys have to be programmed by a dealer ship or locksmith via a computer. You can’t have these keys copied at any hardware store or auto parts store.When a transponder key is lost or needs replaced, many people will typically return to the dealer to have a duplicate or replacement made.