EFFICIENT UNDENIABLE THRESHOLD PROXY SIGNATURE SCHEME.

The threshold proxy signature scheme allows the original signer to delegate a signature authority to the proxy group member to cooperatively sign message on behalf of an original signer. In this paper, we also propose a new scheme which includes the features and benefits of the RSA scheme which is a popular security technique. Also, we will evaluate a security of undeniable threshold proxy signature scheme with known signers. We find that the existing threshold proxy scheme is insecure versus the original signer forgery. We also demonstrate that a threshold proxy signature suffers from a conspiracy of an original signer and a secret share dealer, and that the scheme is commonly forgeable, and cannot offer undeniable. We claim that the proposed scheme offers the undeniable characteristic. [ABSTRACT FROM AUTHOR]