Method and apparatus for performing complex pattern matching in a data stream within a computer network

• Main Authors: DAVIS GORDON TAYLOR, STROLE NORMAN CLARK, LINGAFELT CHARLES STEVEN
• Format: Patent
• Language: English
• Published: 30.09.2004
• Edition: 7
• Subjects: ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHICCOMMUNICATION

An apparatus for performing complex pattern matching in a data stream within a computer network is disclosed. The apparatus includes a serial array register and a content-addressable memory (CAM). The CAM includes multiple CAM entries, and each of the CAM entries includes a k-byte pattern concatenated with an n-byte mask. The positions of the k-byte pattern and n-byte mask in each of the CAM entries offset from those in other CAM entries by one byte. Preferably, the k-byte pattern is each of the CAM entries represents a known computer virus pattern. After the capture of a data pattern from a data stream by the serial array register, the CAM register performs a comparison operation between the captured data pattern and all the CAM entries. If there is a match between the captured data pattern and one of the CAM entries, the CAM signals that the data stream contains information that are potentially harmful to the computer network.