| 摘要 |
<p>A secure proxy signing device for producing digital signatures of documents and supplying the digital signatures over an insecure network provides security measures against a phony document hash being presented by an impersonator of a user to the signing device for forming the digital signature on behalf of the user. In the user equipment there is formed a first data item I1 which is an encrypted hash of the document to be signed and a second data item I2 which is formed by hashing together the document hash (H0), a random number (RN) received from the signing device, and user identifying data (U) which is obtained from a physically present user. The first and second data items are received by the signing which decrypts the first data item to determine the document hash (H0), forms a derived second data item by hashing together the determined document hash (H0), stored last generated random number RN, and user identifying data (U), and comparing this derived data item with the received second data item I2. If the compared items are the same, the determined document hash is authenticated, and it is encrypted with the stored user's private key to form the digital signature (DS).</p> |
