N.Y. Mult. Dwell. Law § 51-C
Every tenant of a multiple dwelling, except a tenant of a multiple dwelling under the supervision and control of a municipal housing authority, occupied by him, except as a hotel or motel, or college or school dormitory, shall have the right to install and maintain or cause to be installed and maintained in the entrance door of his particular housing unit in such multiple dwelling, a lock, separate and apart from any lock installed and maintained by the owner of such multiple dwelling, not more than three inches in circumference, as an ordinary incident to his tenancy, provided that a duplicate key to such lock shall be supplied to the landlord or his agent upon his request; and every provision of any lease hereafter made or entered into which reserves or provides for the payment by such tenant of any additional rent, bonus, fee or other charge or any other thing of value for the right or privilege of installing and/or maintaining any such lock, shall be deemed to be void as against public policy and wholly unenforceable.
N.Y. Mult. Dwell. Law § 51-C