A signature verification system, which comprises a plurality of worn devices of signing users, each provided with one or more motion sensors, and a processor for receiving motion signals from the sensors, the processor is adapted to define a set of features that describe a signature and distinguish one signature from another; perform a training phase by obtaining motion signals from one or more motion sensors of the worn devices; training a machine learning classifier using the instances and labels; obtain motion signals from motion sensors of the a worn device, the motion being of an allegedly genuine signature of one of the users; scale and domain transform the allegedly genuine signature; calculate values of the features describing the allegedly genuine signature with respect to scaled and transformed reference signatures of the one of the users; and apply the trained classifier on the feature values, thereby classifying the allegedly genuine signature as genuine or forged.