Abstract: Digital fingerprinting schemes are cryptographic techniques for supporting copyright protection of digital data.This paper extends the state of the art group signature of Camenisch and Groth，which is considered to be highly efficient at present，and on that basis presents a practical anonymous fingerprinting scheme.This scheme’s main merits make it practical for applications.More precisely，after the registration the buyer can purchase the preferred data anonymously，and the number of transactions is unlimited.In addition，as opposed to an ordinary group signature scheme，there is no fixed revocation manager.Instead，the buyer himself chooses a secret for traceability and takes the role of the revocation manager.It can be proved that the new protocol fulfills the following properties，i.e.，the security of the merchant，the buyer and the registration center，as well as buyer’s anonymity.

Key words: copyright protection, anonymous fingerprinting, group signature, traceability

摘要： 数字指纹方案是一种能实现对数字数据进行版权保护的密码机制。对目前较为高效的由Camenisch与Groth提出的群签名方案进行了扩展，提出了一个实用的基于群签名的匿名数字指纹方案。新方案有如下实用特点，即客户注册成功后可以匿名地购买所需数据，且不受购买次数限制。另外，与普通群签名不同，群体中不设固定的身份撤销管理员，而是由客户自行选取用于进行身份追踪的秘密信息并充当这个角色。可以证明，新方案确保了商家、顾客、注册中心的隐私，以及顾客的匿名性。

关键词: 版权保护, 匿名数字指纹, 群签名, 可追踪性