New York Consolidated Laws, Real Property Actions and Proceedings Law - RPA § 923. Security for credit on sale

The portion of the purchase-money for which credit is allowed in the interlocutory judgment shall be secured at interest by a mortgage upon the property sold, with a bond of the purchaser;  and by such additional security, if any, as the court prescribes.  The officer making the sale may take separate mortgages and other securities in the name of the county treasurer of the county in which the property is situated for such convenient portions of the purchase-money as are directed by the court to be invested;  and in the name of the owner, for the share of any known owner of full age who desires to have it invested.