A LATTICE-BASED RING SIGNATURE SCHEME WITHOUT TRAPDOORS

In order to solve the problems of low computational efficiency, large storage overhead and weak security of existing lattice-based ring signature, a lattice-based ring signature scheme without trapdoors is constructed. The scheme was constructed under the assumption of approximate shortest vector problem (����SVPy​), which was equivalent to solving the collision problem under (��+1)(xn+1)-cyclic lattice and extracted the key by using the properties of anti-collision Hash function. And the scheme used neither Gaussian sampling algorithm nor trapdoor generation algorithm. All operations were linear operations in ring �=���/(��+1)R=Zp​x/(xn+1), which reduced the computational complexity. Compared with the existing ring signature schemes, it has better computational efficiency, and its security under the random oracle model is proved. The scheme meets the anonymity under the condition of complete key exposure and the strong unforgeability of adaptive selective message attack.