Recently, an improved digital signature scheme was
proposed by He. However, there is a weakness in He’s
scheme, where the forgers can forge valid signatures.
In this paper, we show that there is also a drawback
that a public key may have more than one
corresponding secret key, where the verifier cannot
determine who the real signer is. As a result, we
improve He’s scheme to overcoming the above flaws.
Moreover, we propose a message-passing protocol. In
the proposed protocol, the delivered message can be
extended by the valid senders, and the appended
signatures are used to ensure the integrity of the
message and to verify each signer of each sub-message.
2005 International Conference on Cyberworlds , pp. 93-100 , 2005-11. Singapore.