Improved broadcast encryption schemes with enhanced security
A broadcast encryption scheme is one of important primitives to achieve message confidentiality in distributed network, which supports one-to-many encryption under insecure channels. In this paper, we show that any balanced incomplete block design constructed by perpendicular array can be used to realize secure BE schemes. Its broadcast rate, broadcast information rate and the upper bound of the number of collusion resistant are also obtained. According to the characteristics of the block, a more efficient broadcast encryption, using the strong part balanced incomplete block design constructed by rational normal curve is presented. This scheme is secure under an enhanced security model compared with the first construction. Particularly, even any two users are absent in the block, it can achieve fully collusion resistant. Moreover, an improved scheme is given based on the efficiency comparison of these two schemes, in which the broadcast rate is invariant while its broadcast information rate is significantly higher than that of the first construction. Finally, we propose a block reservation scheme, which provides the function of appending users dynamically.
broadcast encryption block designs dual designs forward secrecy