| 摘要 |
<p>PURPOSE: To authenticate the genuineness of the hard copy by generating a digital signature from an original by means of a copier to give a copy and constituting the copy of the original of a digitally signed document. CONSTITUTION: A block 62 generates the digital signature by an existent algorithm with the use of a user's secret sign key and this digital signature is given to an optical copy prepared from the original of the document. The combination of this optical copy and the digital signature is executed by a block 64. On the side of reception, a document 35 placed on a device is a signed document and in this case, the role of this device is confirming whether the digital signature appearing at the signed document is valid or not. Then after a block 66 checks the digital signature, when the digital signature is not valid, e.g. the device is programed so as not to immediately copy but displays a message showing that the hard copy on the device is not authenticated.</p> |
