Study On Partially Blind Signature And Its Application In Reputation Mechanism For The Mobile Crowd Sensing System

In recent years, with the constant innovation of science and technology, the main methods of people’s communication, information sharing and accessing to services have changed from face to face for the use of smart phones, tablets and other typical of mobile devices, in which all kinds of the sensors integrated. The sensory information can be uploaded to the server through Wi Fi, 3G mobile network and the others. The server analysis and proceses these information, ultimately returns feedback to users, this emerging field is called mobile crowd sensing system. The process of perception data acquisition and information uploading will involve the users’ privacy information inevitably, which will be a threat to the users’ security. If the mobile crowd sensing system would move to large scale, security mechanism is the key technology. In this thesis, we propose a new partially blind signature algorithm, and design a reputation machanism for the mobile crowd sensing system. Finally, we make a simulation about the proposed algorithm and give a depth analysis of the performance.Blind signature plays a central role in applications such as e-cash and e-voting systems. Though it can effectively protect the privacy of users, it also exists the contradiction between anonymity and controllability. To solve this problem, partially blind signature adds some public information negotiated by signer and user. In this thesis, we propose a new efficient identity-based partially blind signature. The scheme is proved to be existentially partially blind and unforgeable against adaptive choicen message and identity attacks in the random oracle model, and the security can be reduction to the computational diffie-hellman difficulte problem. Compared with the existing partially blind signature schemes, the proposed scheme has better computational efficiency and less communication.In this thesis, the simulations of the proposed identity-based partially blind signature and others existing schemes are proceed under Linux OS using the PBC database. The simulations including the running time test in each stages, the user and signer’s operation time and calculation consumption of the schemes. The results are shown in histogram. It is obviously that the proposed scheme has lower computational complexity, less mutual information and higher computation efficiency.Reputation mechanism is an important technique to ensure that the agreement can be carried out smoothly. For individual recessive incentive mechanism, the key technology is identity management. Reputation mechanism is to protect the privacy of users who need to hide the correlation between themselves and their reputations. If users have any abnormal behavior, the reputation mechanism can track the users’ identity information. Based on the proposed identity-based partially blind signature and PEPSI security architecture, we design a reputation mechanism for mobile crowd sensing system, and give the specific process of users’ registration and login. At last, the related algorithm of this system is proved which shows that the system satisfies the security requirements of anonymity and unforgeable, and it can trace users’ identity by computing information. The traceability can reach the purpose that encourage good behavior and punish inappropriate behavior.