N.Y. Comp. Codes R. & Regs. tit. 21, § 505.4 – Proof of identity.

(a) When records or personal information are made available in person following a written request from a data subject, the authority may require appropriate identification, such as a driver's license, an identifier assigned to the data subject by the authority, a photograph or similar information that confirms that the record or personal information sought pertains to the data subject. When a request is made by mail, the authority may require verification of a signature or inclusion of an identifier generally known only by a data subject, or similar appropriate identification that confirms that the record or personal information sought pertains to the data subject.
(b) Proof of identity shall not be required regarding a request for a record or personal information accessible to the public pursuant to article 6 of the Public Officers Law.