1. A computer-implemented method comprising: identifying, by a policy management system comprising a first processor, data to be protected based on a security policy, wherein the data comprises tabular-formatted data comprising a plurality of cells; deriving, by the policy management system, an abstract data structure from the identified data by generating an entry of the abstract data structure for a first cell of the plurality of cells of the tabular-formatted data based on a placement of the first cell in relation to the plurality of cells, wherein the entry comprises a row number of the first cell, a column number of the first cell, and a data type indicator associated with the first cell, and wherein the abstract data structure does not reveal sensitive data elements of the data; and sending, by the policy management system, the abstract data structure and information regarding the security policy over a network to a message monitoring system comprising a second processor, to enable the message monitoring system to perform content searches on a plurality of messages electronically transmitted to reach respective destinations, the content searches to be performed based on the security policy to determine whether one or more of the plurality of searched messages contains at least a portion of the data to be protected using the entry of the abstract data structure for the first cell of the plurality of cells of the tabular-formatted data.