1. A computer implemented method for a computer system having a memory and at least one processor, the method comprising: storing, by the processor, an index derived from confidential data having a tabular structure, wherein the index defines the tabular structure of the confidential data; receiving, by the processor, information content; detecting, by the processor, in the information content, a sequence of content fragments that is indicative of containing a portion of the confidential data; determining, by the processor, whether a subset of content fragments within the sequence matches any sub-set of the confidential data using the index derived from the confidential data; and performing, by the processor, a data loss prevention action based on results of determining whether a subset of content fragments within the sequence matches any sub-set of the confidential data.