Anonymous IBE from Quadratic Residuosity with Fast Encryption

Xiaopeng Zhao, Zhenfu Cao, Xiaolei Dong, Jinwen Zheng

Abstract: We develop two variants of Cocks’ identity-based encryption. One variant has faster encryption, where the most time-consuming part only requires several modular multiplications. The other variant makes the first variant anonymous under suitable complexity assumptions, while its decryption efficiency is about twice lower than the first one. Both the variants have ciphertext expansion twice more extensive than the original Cocks’ identity-based encryption. To alleviate the issue of the second variant’s large ciphertext expansion, we consider using it to construct a public-key encryption with keyword search scheme with a fast encryption algorithm by means of the transform in [1].