A Group Signcryption Sheme Based on Chameleon Hash Functions

• Main Authors: Chuang-yao Lai, 賴瓊瑤
• Other Authors: Wei-Ning Yang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/97804194103881865061

碩士 === 國立臺灣科技大學 === 資訊管理系 === 101 === In corporate applications, we often do not want to go through the complicated procedures before receiving the required documents or information, especially for those which provides many services for the users. In order to enhance the efficiency, the company groups may have representatives to provide services for users. The spirit of group signature is that any company member may sign the document or message signature on behalf of the company. When a company member provides business service to us, we would always expect to get some discounts or rewards. However the company representatives often do not want us to share the discount information to the others, which may lead to the company loss. "Non-transferability" on the chameleon hash function can assist us on achieving the demand base characteristic. However, when the company provides services, trading, and sending the message to users, we have to retain a document or message privacy. So it is necessary to combine signature and encryption mechanisms. In order to reduce traditional signatures and encryption cost of a two-stage, we based on the chameleon hash functions combine group signature and signcryption. When the sender sent the signcryption text to the receiver, the recipient can verify the signature as a valid group signcryption text. The receiver cannot transfer the signcryption text to others. In order to reduce the costs necessary to arbitration disputes, the signcryption text is allowed the recipient to change the signcryption text into ordinary signature. According to the method proposed in this study, based on chameleon hash functions combined the group signature and signcryption characteristics that have the following advantages: 1. In order to improve the efficiency of the signcryption procedure, members of the group can behalf of the group product the signcryption. 2. In order to reduce traditional calculation time and transmission costs of two-stage signature and encryption by signcryption mechanisms. 3. We can achieve the necessary about group member anonymity, group signcryption text repudiation, confidentiality, integrity, and authenticity. 4. In order to protect their group interests to achieve non-transferability, the recipient receives the group signcryption and recipient cannot transfer the signcryption text to other people. 5. When the event of a dispute： (1) Group undenied who produce the signcryption text. (2) Groups can deny the group signcrypted if the recipient forging. (3) System Authority can track the actual signer in the group.