16. A non-transitory computer readable storage medium that provides instructions, which when executed on a processing system cause the processing system to perform a method comprising: storing, in memory, a plurality of classified data patterns for personal identifiers, the plurality of classified data patterns corresponding to variations of personal identifier formats, the personal identifiers including confidential information of a plurality of entities; identifying a text document to be searched; searching the text document for data expressed in a format that matches any of the plurality of classified data patterns corresponding to the variations of personal identifier formats; finding, in the text document, one or more personal identifier candidates matching any of the plurality of classified data patterns; and validating each of the personal identifier candidates using one or more personal identifier validators to provide accurate detection of the confidential information in the text document.
19. The computer readable storage medium of claim 16 wherein validating each of the personal identifier candidates comprises: eliminating preliminary false positives based on data immediately preceding or following each of the personal identifier candidates; and applying a list of validators to remaining candidates to eliminate additional false positives.