Based on symmetric bivariate polynomial, this paper proposes a new fair(t n) threshold secret sharing scheme,which can guarantee that each participant can recover the correct secret if all participants are legal and honest; when there is a cheater, all participants are unable to recover the correct secret. In the proposed scheme, a symmetric bivariate polynomial is used to generate session key for any two participants; moreover, combined with discrete logarithm, the symmetric bivariate polynomial enables t...