Revocable ID-based signcryption scheme

In order to revoke private key leaks or malicious users in a signcryption system, a new revocable identity-based signcryption scheme was proposed. In this scheme, the master key was randomly divided into two parts, which were used to construct the initial key and generate updated key, respectively. Furthermore, they were used to generate (designcryption) signcryption key randomly, thus the proposed scheme can revoke users and resist key compromise attack. In the standard model, it was shown that the new scheme has IND-CCA2 security under the hardness of DBDH problem and EUF-CMA security under the hardness of CDH problem.