N.J. Stat. § 19:52-7
The keys of each voting machine shall be inclosed in an envelope to be supplied by the county board of elections or the superintendent of elections or the municipal clerk, as the case may be, having custody of voting machines, on which shall be written the number of the machine and the district and ward where it has been used, which envelope shall be securely sealed and indorsed by the district election officers, and shall be returned to the source from which the keys were received. The number on the seal and the number registered on the protective counter shall be written on the envelope containing the keys. All keys for any voting machine shall be kept securely by the officials having them in charge. No unauthorized person shall have in his possession any key or keys of any voting machine and all district election officers or persons intrusted with such keys for election purposes, or in the preparation of the machine therefor, shall not retain them longer than necessary to use them for such legal purpose. All machines shall be stored by the county board of elections or the superintendent of elections or the municipal clerk, as the case may be, having custody of voting machines, as soon after the close of the election as possible, and the machines shall at all times be stored in a suitable place, which place shall be a fireproof public building in such counties or municipalities, as the case may be, as have same.
N.J.S. § 19:52-7