International Association
for Cryptologic Research

Recently, Xiong et al. [H. Xiong, Z. Guan, Z. Chen, F. Li, An Efficient certificateless aggregate signature with constant pairing computations, Information Science, doi: 10.1016/j.ins.2012.07.004, 2012] proposed a certificateless signature (CLS) scheme and used it to construct a certificateless aggregate signature (CLAS) scheme with constant pairing computations. They also demonstrated that both of their schemes are provably secure in the random oracle model under the computational Diffie-Hellman assumption. Unfortunately, by giving concrete attacks, we point out that Xiong et al. schemes are not secure in their security model.