1. A method comprising: identifying, by a client device, an index derived from preselected data having a tabular structure, wherein the index defines the tabular structure of the preselected data and comprises positional information identifying relative placement of data elements of the preselected data in relation to other data elements of the preselected data, and wherein the index does not reveal sensitive data elements of the preselected data; determining, by the client device, whether at least a portion of the preselected data having the tabular structure is possibly contained within information content; and in response to determining that a portion of the preselected data is possibly contained within the information content, performing, by the client device, a search of the information content for at least a portion of the preselected data using the index derived from the preselected data.