Patent ID: 7162638

Claim:
An electronic data management system for using electronic data mutually among a plurality of computer systems classified into at least a first computer system and a second computer system, the first computer system and the second computer system being in communication with each other, the first computer system comprising: reference characteristic value extraction means for extracting a reference characteristic value from a copy of electronic data attached with a reference characteristic value obtained from original electronic data, the copied electronic data attached with the reference characteristic value being generated by and transmitted from the second computer system and received by the first computer; comparison subject characteristic value calculating means for calculating a comparison subject characteristic value from the copied electronic data and recopied electronic data from the original electronic data from the first computer system; and determination means for determining authenticity of the copied electronic data from the second computer system and the recopied electronic data from the first computer system by comparing the reference characteristic value and the comparison subject characteristic value, wherein the copied electronic data transmitted from the second computer system to the first computer system is capable of being compared with three-dimensional geometry of a manufactured product only by using a laser beam of the first computer system.