Certificateless Aggregate Signature Without Trapdoor for Cloud Storage

In this paper, we propose a lattice-based certificateless signature scheme and certificateless aggregate signature which can be used to verify a large number of signatures simultaneously efficiently. To improve the security of our scheme, we have implemented our signature algorithm without trusted third parties. The security of our proposed signature algorithm can be reduced to the SIS problem under the random oracle model. Moreover, our construction only needs matrix multiplication and rejection sampling operation, so the algorithm is naturally simple and efficient. Besides, we've done some experiments using the NTL library, indicating our scheme has less time overhead and storage overhead than other schemes. To our best knowledge, we propose the first certificateless aggregate signature without trapdoors.