Efficient Chosen Ciphertext Secure Public Key Cryptosystem
from the ID-Based Encryption of Waters
Mei Qi-xiang①②③;He Da-ke①; ZhengYu①
①School of Computer Science and Communication Engineering, Southwest Jiaotong University, Chengdu 610031,China ②State Key Laboratory of Information Security , Graduate School of Chinese Academy of Sciences, Beijing 100039, China; ③School of Information Science and Engineering, Central South University , Changsha 410075, China
Abstract：In Eurocrypt 2004, Canetti, Halevi and Katz proposed a method for constructing Chosen Ciphertext secure ( ie., CCA secure) public key encryption from any Selective-ID secure ID-Based Encryption (IBE). However, this method needs one time signature and thus adds noticeable overhead to the underling scheme. In this paper, a new CCA secure public key cryptosystem is constructed from the Adaptive-ID secure IBE scheme proposed by Waters. Here, the “identity” is the hash of the first two parts of the ciphertext, and the bilinear map is used to test the ciphertext validity. The proposal is much more efficient than those obtained from the general CHK method. The security of the new scheme is proved under the standard Decisional Bilinear Diffie-Hellman (DBDH) assumption.
2006, Vol. 28 
