An important characteristic of ink-on-paper signatures is that they can be individually studied and analyzed by forensic handwriting experts, then compared to other existing samples for authentication. Perhaps the most significant challenge to the validity of an electronic signature is the issue of authentication, since few technology providers support their technology with verification tools. If a signature cannot be attributed to the purported signatory, it is worthless. Electronic signatures are no exception to this, and must be capable of authentication to be valid and binding. Insist that a technology provider have authentication tools and training in-place before selecting their solution.

The most accurate, reliable, and secure method of capturing a signature is in the form of raw pen events. A file of this type contains no images or analysis of the signature, just the pen events and position converted at high speed. This data has the additional advantage of being stored in a database or bound to the contents of a document very securely. It cannot be easily copied or viewed and used as a reference for forgers since there is no embedded image. Furthermore, all original captured pen events are present in the e-signature itself.