The burden of proving the existence, terms, and validity of a contract rests on the party seeking to enforce it. This requires, in the first instance, authentication of the purported writing. Authentication may be effected by various means, including, for example, by certificate of acknowledgment, pursuant to CPLR 4538, by comparison of handwriting, pursuant to CPLR 4536, or by the testimony of a person who witnessed the signing of the document. If the signature is forged, the contract is void ab initio.
Knight v. New York & Presbyt. Hosp., NY Slip Op 04258 (1st Dep't August 10, 2023)
