| 摘要 |
PROBLEM TO BE SOLVED: To not only judge whether or not alteration is performed but also detect which part of a general text document and the other so-called word processor document is altered especially in the alteration detection of an electronic document in an electronic signature and recognition device for writing a signature which is the proof of an individual in the electronic document and performing authentication. SOLUTION: For the text document, the line feed codes are retrieved, a message digest which is electronic signature data is prepared from the text document between the respective line feed codes and the message digest is ciphered and transmitted through a network along with the original text document. In the meantime, on a computer side for instance which receives the text document and the ciphered electronic signature data, the message digest is prepared from the text document first, the ciphered electronic signature data are deciphered and turned to the message digest, both data are compared, and when both data do not match, it is defined that they are altered and the text document between the corresponding line feed codes is recognized. |
