A Revocation Scheme from the Weil Pairing

• Main Authors: I-Chao Chen, 陳怡超
• Other Authors: Wen-Guey Tzeng
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/86563885868141305283

碩士 === 國立交通大學 === 資訊科學系 === 91 === A Revocation Scheme from the Weil Pairing Student：I-Chao Chen Advisor：Dr. Wen-Guey Tzeng Institute of Computer and Information Science National Chiao Tung University Abstract We deal with the broadcast encryption system that a center sends a message to a group of users which some of them are revoked and can not decrypt the message. We concentrate on stateless receiver case, where receivers can not update their private information from session to session. We propose a subset-cover revocation algorithm based on Weil Pairing. The algorithm is pretty flexible that it can revoke any users and efficiently send messages to privileged users. Even the coalition of the revoked users can not decrypt the message. Besides, our revocation scheme has the tracing property also. In our scheme, each user stores N private keys and in order to revoke r users, the message length which the center transmits is r+1 at most. Every user only needs to decrypt one time when receiving the message. Our method is better than previous proposed methods with respect to the required message length. (N is the number of total users, r is the number of revoked users) Key words：Broadcast Encryption System, Revocation Scheme