A response to a critique of 'A novel electronic cash system with trustee-based anonymity revocation from pairing,' by Chen, Chou, Sun and Cho (2011)

We provide a brief rebuttal of Chang (2012), who suggested that there were flaws in our article, Chen et al. (2011), that deserved further investigation and comment. We believe that these criticisms are unfounded, and offer some additional details related to the intractable discrete elliptic curve discrete logarithm problem to further support the case we wish to make.