Abstract
Previously, all of the proposed threshold proxy signature schemes which have been based on the discrete logarithms required a protocol to generate and verify a shared secret among the proxy group. Therefore, it is necessary for the proxy signers to execute a lot of expensive modular exponential computations and communications to obtain and verify a shared secret. Thus, it is very time-consuming to construct the proxy signature. Moreover, some of the existing threshold proxy signature schemes reveal that the receiver cannot find out who signed the proxy signatures. In this paper, we proposed a practical, efficient, and low communications (t, n) threshold proxy signature scheme based on RSA cryptosystem. By using our way, not only the original signer can know who generated the proxy signature, but also everyone can be a verifier to certify the actuality of the group signers who made it. So, it is very convenient to clarify the responsibility of the document's signers fairly.