A new forward-secure threshold digital signature scheme which based on multiplicative secret sharing and strong RSA assumption is put forward in this paper. The scheme has the following property: It have the property of forward security, even if more than the threshold numbers of players are compromised, it is not possible to forge the signature which is related to the past. This property is achieved while keeping the public key fixed and updating the secret keys at regular intervals. Assuming

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... hat factoring is hard, we proved that this scheme is security in the random oracle model. key-evolving threshold signature scheme can tolerate at most t corrupted players and works as follows. Key generation phase. Given a security parameter k , the public and the secret keys are generated and distributed to the players. This can be accomplished with a trusted center. Key update phase. At the start of each time period, an update protocol is executed among any subset of u k non-corrupted players. The protocol modifies the secret key for the signature scheme. After the update protocol is executed, each non-corrupted player will have a share of the new secret for that time period. Forward-secure schemes require that the secret key from the previous time period be deleted from the user's machine as part of the update protocol. Signatures generation phase: To generate signatures, a subset of s