Identity-Based Encryption based on DHIES

摘要

Most traditional public key cryptosystems are constructed upon al gebraically rich structures, which makes their key pairs combin able, i.e., the combination of some private keys and their corre sponding public keys could form a new key pair. Exploring such combinable property, this paper proposes a novel Identity-Based Encryption (IBE) scheme based on the Diffie-Hellman Integrated Encryption Scheme (DHIES) with quadratic key combination struc ture from bilinear maps. The new scheme has a number of advan tages over other IBE schemes. First, it uses DHIES to fulfill en cryption, thus naturally obtains the security against adaptive chosen ciphertext attack from DHIES. Second, it is interoperable with ex isting security systems based on DHIES. Third, compared to many pairing-based IBE schemes, it only requires pairing computation during public key generation and there is no need for special hash function. We prove that our scheme is selective identity chosen ciphertext secure in the random oracle model assuming DHIES is chosen ciphertext secure. Additionally, the extract algorithm of our scheme also implies an identity-based short signature scheme.