摘要：People in authority may want to submit some messages anonymously on a famous website, while the maintainers may want to limit the times each person can submit messages on the website so as to save the storage space. More over, when people abuse the system, the maintainers want to find ways to identify their identities. To realize such a system, what we need are some methods that can protect users’ privacy, control their access times, and at the same time can identify malicious users when abuses are found. Current sig- nature schemes or credential systems cannot fully achieve above purpose. A single-verifier k-times group signature scheme is proposed, adding times limited property to the group signature scheme. It allows a user to issue group signatures to the only verifier up to kitimes for period Ti. We use online tracing method to restrict each user to kisignatures strictly, and use the tracing ability of group signature to identify those who abuse the system. Based on it, we can construct times limited accountable anonymous online sub- mission control system for websites. Within allowed times, people can submit articles anonymously, even website maintainers cannot identify two articles are from the same person. When a person posts more than the allowed times, his submission will be rejected. When abuse is found, website maintainers can send the signature to the corresponding open authority to find out the identity.
关键词：privacy; anonymous authentication; accountability; group signature
