A method and device for registering a handwritten personal signature and for judging its authenticity by comparison with previously registered measured values and data derived therefrom. Signature data is acquired by registering a signature handwritten on a surface by a three-dimensional inertial sensing system having rate-of-rotation sensors and linear acceleration sensors. The data is subjected to a subsequent procedure of recognition or verification or comparison with other signatures. Hence not only tracking is performed with reference to the tip of a writing implement, but the dynamics of the signature are registered and evaluated by numerical calculation and adopted as the basis for the subsequent comparison, effectively ruling out the possibility of fraudulent duplication or tracing-over of a signature by an unauthorized third party. The dynamics i.e. acceleration and deceleration phenomena and rates of rotation as the signature are executed and effectively registered. From them, supplementary measured variables are calculated and specific characteristics are defined from those variables. Those variables are adopted as the basis for comparison, the degree of accuracy of the verification that the signature is genuine can be substantially increased.