Electronic document security system, affixed electronic seal security system and electronic signature security system

摘要

An electronic document security system, a fixed electronic seal security system, and an electronic signature security system. A method for security coding a document uses a symbolic figure such as a signature or a seal. An electronic document including a symbolic figure is stored. The electronic document is encoded in accordance with a confidential key and a predetermined characteristic is extracted from the encoded electronic document. The symbolic figure is then modified in accordance with the characteristic. The confidential key and the symbolic figure may be stored in a portable media to increase the security.