Comment: A new blind signature based on the discrete logarithm problem for untraceability

摘要

In 2004, Lee et al. [C.C. Lee, M.S. Hwang, W.P. Yang, A new blind signature based on the discrete logarithm problem for untraceability, Appl. Math. Comput., in press] proposed a new untraceable blind signature based on DLP in order to overcome the “security limits” of Carmenisch et al.’s scheme. However, we show there are two mistakes in [C.C. Lee, M.S. Hwang, W.P. Yang, A new blind signature based on the discrete logarithm problem for untraceability, Appl. Math. Comput., in press]: 1. The Carmenisch et al.’s scheme does meet the requirement of untraceability and the cryptanalysis proposed by Lee et al. is not correct; 2. Though Lee et al.’s scheme is untraceable, the proof of its untraceability in [C.C. Lee, M.S. Hwang, W.P. Yang, A new blind signature based on the discrete logarithm problem for untraceability, Appl. Math. Comput., in press] is wrong (in this paper we also give the correct proof of its untraceability). So Lee et al.’s scheme does not have any advantage and it is unpractical since the cost of the scheme is higher compared with Carmenisch et al.’s scheme.