Methods and systems for exact data match filtering

A technique for efficiently preventing exact data words ("entities") from unauthorized disclosure is disclosed. Protect agents installed at various egress points identify candidate entities from digital information desired to be disclosed by a user. The candidate entities are compared against registered entities stored in a lightweight entity database (LWED). If a candidate entity matches against a registered entity in the LWED, the protect agent initiates a security action. Alternately, the protect agent transmits the matching candidate entity to a global entity database (GED) server to receive additional confirmation on whether the candidate entity matches a registered entity. In some instances, the protect agent also receives (from the GED server) metadata information associated with the matching candidate entity. The protect agent utilizes the metadata information to initiate suitable security actions.