| 摘要 |
PROBLEM TO BE SOLVED: To enable display of seal impression and print of a document with the seal impression and to electrically verify that the impression is given to the document by a person himself who recognizes the document by generating a message digest from electronic seal impression and superposing the message digest on the electronic seal impression itself. SOLUTION: A seal impression image file 12 of the person to recognize the document is created by using a scanner, etc., on the transmitter's side. Next, a hash value (message digest) for preventing manipulation is generated from the created seal impression image file 12. A signature (ciphering) is executed by the person's own private key to assure deniability for the created hash value. Then the signature is embedded in the seal impression image file 12 by electronic watermark technology for individual identification of the seal impression 18 itself. On the other hand, a signature part of the seal impression 18 itself is extracted and separated from the seal impression image file 12 and decoded by the public key of the person to recognize the document on the receiver's side. Subsequently, the hash value is generated from the seal impression image file 12. |
