Cryptanalysis of Zheng et al.'s Pairing-free Secure IBE Scheme

Recently, Zheng et al. proposed a provable secure IBE scheme without bilinear map under standard security model where it is claimed that their constructed scheme is secured against adaptively chosen ciphertext attack. On cryptanalysis, we show through the derivation and solution of a set of linear congruence that their scheme is vulnerable to the key compromisation attack, thus, the message confidentiality is also compromised. Furthermore, our claim is justified by developing an alternative method based on the hamming distance of users identities.