Forensic Document Examination of Electronically Captured Signatures

Document Type


Publication Date



Biodynamic signature systems are a means by which a person provides a signature in electronic format that is reproduced on the screen as a representation of their manuscript signature. These systems use software to record measurements when a person uses the device to produce a digital version of their handwritten signature. The measurements recorded include dynamic time-based measurements such as duration, velocity, air strokes, and pressure as well as static form-based measurements such as slant, length, height and shape. The combined data recorded establishes a unique signature profile of the person at the time of writing. The temporal, time-based features differ significantly from the static ink traces on paper documents that forensic document examiners typically analyze. Recommended procedures in forensic analysis include the acquisition of computer files and analysis of temporal features. Due to the varying quality of the data acquired by electronic signature systems, not all systems produce reliable information to support forensic opinions. A recent legal ruling in the U.S. underscores the need for forensic document examiners to examine electronic evidence in biodynamic signature cases. Working collaboration between forensic document examiners and computer experts is recommended.