支持电路结构的多线性映射属性签密方案

Attribute-based Signcryption for Circuits from Multi-linear Maps

属性基密码体制既克服了传统密码体制访问控制单一的缺点,又能同时实现对机密性和不可伪造性的保护。设计了一个多线性映射属性签密方案,方案以Sahai等提出的支持多线性映射的单调电路作为访问结构,并引入运算外包策略,方案能够够支持任意扇出,降低了解签密者的计算代价。同时在k阶多线性假设下证明了方案的安全性。与一般属性签密方案相比,当属性个数无穷大时解签密者的密钥传输效率可提高约66.7%,签密文长度固定,与属性个数无关,解签密者的运算量仅为8p+(n+3)e,此外方案还满足可公开验证性,可应用到社交网络等新型网络应用中。

Attribute-based signcryption provides not only the chance that the participants access the cipher texts by their attributes in- stead of identities, but also the combined security of confidentiality and unforgeability. An attribute-based signcryption scheme from multi-linear maps was proposed. The circuits presented by Sahai et. al was used as the access structure to support the arbitrary fanout, and the outsouroing computing was employed to reduce the receivers＇ computational cost. The security was evaluated in the standard model under the k-decision multi＇linear problem assumption. Compared with the existed schemes, the decryptor saved the key commu- nication cost up to 66.7%. Furthermore, the constant cipher texts were kept after being outsourciug computed. The computational cost of the receiver was 8p ＋ （n ＋ 3） e. Additionally, this scheme could be verified publicly and gives the foundation of performing secure communication in social networks and others.