1. A method performed by a device for generating a shared secret between the device and at least one additional device, the method comprising: measuring an acceleration of the device at least during a time window beginning at a time corresponding to when a magnitude of the acceleration exceeds a threshold; sampling the acceleration to generate a plurality of vectors, a first vector among the plurality of vectors being an initial sample of the acceleration during the time window; calculating dot products between the first vector and each of subsequent vectors among the plurality of vectors, resulting in an array of scalars; reducing a resolution of at least one of the array of scalars or the plurality of vectors; and utilizing at least a portion of the array of scalars to generate the shared secret.