Second-order spectral-null (2-OSN) codes are, in general, constructed from concatenating any codewords in 2-OSN code. Most 2-OSN codes adopt the Tallini-Bose random walk method in encoding and decoding, which exchanges two adjacent bits each time in a binary vector. In this brief contribution, we give a new implementation of the Tallini-Bose random walk method for 2-OSN codes which is shown by experiment to be faster.

Many secure micropayment schemes have been proposed as the desire to support the low-value and the high-volume purchases of some e-commerce applications such as mobile commerce services or web-based interactive video services. However it seems that no one studies how to add the ability of returning changes in micropayment schemes. In this paper, we take the lead in studying the micropayment schemes with ability to return changes (MSRC), which reduce the hash operations in transaction phase. When compared with the previous micropayment schemes, the proposed MSRC have the low computation costs and thus is more suitable and practical for mobile commerce environments, where have the limited computation capability and the limited bandwidth.

A novel and interesting application of RFID was a banknote attached a tag to determine the authenticity of money and to stop counterfeits. At Financial Cryptography 2003, Juels and Pappu firstly proposed a practical RFID banknote protection scheme (RBPS) by using the optical and the electrical (RFID) contacts. RFID-enabled notes can be tracked by the legal law agency and verified by the merchant. However, some effective attacks on the Juels-Pappu RBPS were subsequently proposed. In this paper, we enhance the Juels-Pappu RBPS to conquer such attacks.