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Wang et al have designed a new fuzzy signature scheme based on the discrete logarithm. This scheme has proposed a signature protocol in which the signature can be fairly exchanged between signers. This paper has put forward an improved concurrent signature scheme, which can reduce the numbers of implementing positive protocols and negative protocols when exchange and open the signatures and improve the efficiency of the algorithm. At the same time, the correctness, the non-forgeability and the fairness of the signature can be increased.

Digital watermarking is an important technical measure for Intellectual property right protection. Due to the short lifetime of battery of portable device, reducing the energy consumption in this type of the device is sorely needed. In this paper, we proposed an energy efficient, low complexity, robust and secure watermarking algorithm in DS-CDMA communication. In this method, we spread multiple watermarks patterns with multiple orthogonal spreading codes and embedded them to DCT domain coefficients. In this way, the capacity, robustness and security can be improved simultaneously. In order to reduce power consumption, we proposed a low computational complexity frequency domain transformation for the watermarking embedding for DS-CDMA. Moreover, we propose a new architecture for the watermarking. Test indicates that our proposed method can reduce more than 70% of energy consumption.