On the security of a strong provably secure identity-based encryption scheme without bilinear pairing
N.A. Li, Jong Hyouk Lee · International Journal of Internet Technology and Secured Transactions · 2016
The identity-based encryption scheme enables a sender to generate the ciphertext using a receiver's identity and system's parameters. Because of its convenience, the identity-based encryption scheme has been widely used in many practical applications. Recently, Zheng et al. proposed a new identity-based encryption scheme that operates without bilinear pairing. The authors claimed that their proposed scheme is provably secure in the standard model. However, in this paper, we show that Zheng et al.'s scheme unfortunately suffers from the key comprise problem, i.e., malicious users can deduce the private key of the key generation centre (KGC) through a coalition attack. Subsequently, the adversary can deduce any user's private key with the derived private key of the KGC. Our security analysis confirms that their scheme is not suitable for practical applications.