Based on polynomial secret sharing, we construct a robust forward-secure threshold signature schemes. This scheme have the following property: even if more than the threshold number of players are compromised, it is not possible to forge signatures relating to the past. This property is achieved while keeping the public key fixed and updating the secret keys at regular intervals. The scheme is reasonably efficient in that the amount of secure storage, the signature size and the key lengths do not vary proportionally to the number of time periods during the lifetime of the public key. The proposed scheme is based on the Bellare-Miner forward-secure signature scheme. It is based on polynomial secret sharing and tolerates malicious adversaries. We prove it's secure via reduction to the Bellare-Miner scheme, which is known to be secure in the random oracle model assuming that factoring is hard.
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