在电子医疗档案系统中,用户会频繁更新自己的健康数据.若直接使用现有签名方案保证这些数据的可认证性,在泄露用户身份隐私的同时,也需要大量的计算开销.为了解决上述问题,我们利用属性集合来模糊用户的身份信息,并引入可授权第三方一净化者,提出了一个属性基的可净化签名方案.安全性分析证明,本方案保护了用户的匿名性,同时在标准模型下针对给定策略选择消息攻击具有不可伪造性.通过方案对比分析表明,本方案在有效降低用户签名计算开销的同时,还支持树形访问结构,能在大规模属性集下提供灵活的细粒度访问控制.%In the Electronic Health Record system,users update their health data frequendy.If users keep the authentication of these data with the signature scheme in existence,it will lead to the leakage of their identity privacy and huge computation cost.Aiming at tackling the problems above,we propose a novel scheme called attribute-based sanitizable signature supporting dendritic access structure which obfuscates the user identity with attribute sets and introduces an authorized semitrust third-party—sanitizer.The security analysis demonstrates that our scheme achieves the anonymity of users and is unforgeable under selective-predicate chosen-message attack in the standard model.Through comparison,our scheme not only reduces the signing computation overhead of users,but also supports the dendritic access structure which can provide flexibly fine-grained access control under large-scale attribute sets.
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