Research On Theory And Technology Of Anonymity-controllable

The technology of anonymity is an effective way to protect users'privacy. When the anonymous system provides people with private information protection, it also provides some malicious users the opportunity to carry out sabotages. Therefore, revocable anonymity is studied in this article. Main work is as follows:Firstly, a designated-verifier ring signature scheme is proposed. In the scheme signer's anonymity can be revoked and the signer can prove to verifier that he is the real signer and can not deny signature belonging to him; at the same time, non-signers can deny the signature.Secondly, another signature scheme is proposed in order to solve the problem of the administrators'authority in the group signature. In the scheme, signer's anonymity can only be revoked when the verifier and the administrator cooperate. In addition, the scheme is forward-secure.Thirdly, a common way to provide revocable anonymity is introducing a third trusted party. The weak point is that it needs very high security requirements. A concept of strong anonymity-revocable is put forward and the corresponding signature scheme is proposed. In the scheme, based on idea of RBAC, the authority of the third trusted party is divided and distributed in order to weaken the power of the single third trusted party.