A system and method for activating security mechanisms based at least in part on accelerometer-based dead reckoning wherein accelerometer data, reflecting acceleration in a local coordinate system of a device, is obtained from an accelerometer of a device. Movement of the device is determined based at least in part on the accelerometer data, and, based at least in part on whether the movement of the device exceeds a threshold value, a determination is made whether to change a current security state of the device. If it is determined to change the current security state of the device, the current security state of the device is changed to a new security state.