If a document is alleged to be signed or to have been written wholly or in part by any person, the signature or the handwriting of so much of the document as is alleged to be in that person‘s handwriting must be proved to be in his handwriting.67A. Proof as to[electronic signature - Except in the case of a secure [electronic signature] , if the [electronic signature] of any subscriber is alleged to have been affixed to an electronic record the fact that such [electronic signature] is the [electronic signature] of the subscriber must be proved.]