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.
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. 17. The computer readable storage medium of claim 16 wherein: the personal identifiers comprises one or more of a credit card number, a social security number, an account number, an employee number, a customer or patient number, an IP address, a driver license number, and a license plate number; a list of the plurality of classified data patterns is configurable based on user input; and a list of the validators is configurable based on user input.