摘要 |
The invention relates to a method for the digital signature of a message by a signer having an identity and holding a signature device, in which a public key cryptographic scheme is used. The signer has a public key and two private keys, the second private key being deposited at a reliable third party. For each signing operation, two additional steps are respectively carried out with a separate private key, i.e.: the calculation by the signer of a pre-signature of the message using the first private key, and transmitting the message and the pre-signature to the reliable third party; and the verification by the reliable third party of the pre-signature followed by the calculation by the reliable third party of a signature of the message using the second private key deposited at the reliable third party as well as the pre-signature previously calculated by the signer. |