Most digital signature algorithms are based on RSA algorithm, and traditional secret sharing schemes involve the use of a mutually trusted authority to assist in the generation and distribution of shares that will allow a secret to be protected among a set of participants. In contrast, this paper describes a signature scheme based on elliptic curves and proactive secret sharing. A general protocol is discussed and several related steps of this protocol are presented. Special attention is given to mutually trusted authority-free threshold scheme. The scheme ensures that a system can provide reliable signature services even if some servers fail caused by attacks or failures.