A Certificateless Broadcast Threshold De-signcryption Scheme and its Application to DRM

In this paper, we propose a variation of broadcast encryption, called certificateless broadcast threshold de-signcryption (CL-BTDS), and present a concrete CL-BTDS scheme from the multilinear form. This variation provides the functionality that ensures both confidentiality and authenticity of the broadcast message, and non-repudiation of the broadcaster in a logically single step, meanwhile, overcomes the key escrow limitation of the identity-based cryptography. Multilinear forms are applied here to provide constant size ciphertext. We construct an application case to demonstrate that proposed scheme can be used to provide encryption and authentication simultaneously to distribute digital content in multiple DRM formats.