| 摘要 |
<p>A cryptographic certificate attesting to the authenticity of the original document elements will lose its validity when the cryptographic function underlying the certifying scheme is compromised. The present invention extends the reliability of such a certificate by subjecting the combination of the original certificate and the digital representation of the document to a scheme based on a less vulnerable function using the steps of: obtaining the original document (11); applying the function to the document to create the original certificate (13); combining the original document and the certificate (15); and, applying another function to the combination to create an extended certificate (17).</p> |
