Ownership proofs of digital works allow to justify the copyright claim to the buyers without revealing any secret information and prevent the owner from deceiving without the assumption of the trus ted individual. This paper proposes an ownership proofs scheme for digital works based on proactive verifiable secret sharing and secure multiparty computation. In the proposed scheme, verifiable secret sharing ensures the correctness of ownership secrets and achieves security against cheating participants. Proactive security provides an automatic recovery feature to maintain the integrity and security of secret throughout the lifetime of the scheme. Furthermore,the ownership verification is implemented by using secure multiparty computation and zero-knowledge proofs with homomorphic commitments. Without the assumption of the existence of a trusted individual, the proposed scheme can provide effective computation and discover the dishonesty if not too many individuals collude.