Several years back there was a concept (don't know if it was ever realized) of a "smart bolt". Essentially, it was a bolt that had an integrated electro-mechan

Several years back there was a concept (don't know if it was ever realized) of a "smart bolt". Essentially, it was a bolt that had an integrated electro-mechanical locking mechanism, plus a microcontroller. The idea was that these bolts could be used in places where you wouldn't want them to be removed by just "anyone". One example was head bolts on a car (you can imagine how well that went over). To remove the bolt after it was put in place and "locked" would require a special device that would apply power and a required code to the controller, to cause it to "unlock". Likely this device would be a special kind of wrench or socket. Now, I could see such a device in certain cases - for example, lamp posts or traffic signs (though how often have you heard of people just removing those bolts?). But the application almost always illustrated had to do with cars; that manufacturers would be able to restrict access to repair to only dealers and no one else. I'm not sure if this was why they never were created or not; maybe. I tend to think, though, that the complexity of integrating the required locking mechanism into a bolt while simultaneously ensuring its integrity and strength (especially in the case of say, head bolts), probably was more a factor in it.