Automobile Theft Prevention Using 3D Gesture Key Fob and Cryptography A modern vehicles have been using a key fob from last decade to arm and disarm the vehicles. Once the door of vehicle is close then vehicle is armed and to disarm unlock button of key fob is used. But this system is not more secure. If key fob is stolen then anyone can unlock the vehicle. Hence for preventing a vehicle from theft a 3D gesture key fob will be used. In 3D gesture key fob one gesture will be made in air to unlock the vehicle. It will contain two different 3D gestures, one is REGULAR gesture for owner of vehicle and another is GUEST gesture for the guest i.e. for other users. In addition for high security data transmission cryptography algorithm will be used. This system will also contain features like keypad entry for activate the fuel lines, adjustable motion alarm sensitivity, Fuel cut-off and GPS fencing.