共查询到14条相似文献,搜索用时 140 毫秒
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条件代理重加密(CPRE)可以根据条件对密文进行细粒度的授权,现有的CPRE方案只检查原密文的条件,忽略了重加密密钥的条件符合性,也不对条件信息进行保护,容易造成隐私泄露.该文构造了基于门限的无双线性对条件匿名代理重加密方案(TB-CAPRE),对密文和重加密密钥的条件同时进行验证,并将敏感的条件信息进行匿名化处理,利用门限将重加密分布到多个代理节点完成,能够抵御合谋攻击.理论分析证明了该方案在随机预言模型下满足适应性选择密文攻击下的不可区分安全性(IND-CCA).效率和计算量分析表明TB-CAPRE在增加安全性和相关功能后并没有引入过大的开销,可以应用到分布式环境中. 相似文献
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可搜索加密技术的提出使用户能够将数据加密后存储在云端,而且可以直接对密文数据进行检索。但现有的大部分可搜索加密方案都是单用户对单用户的模式,部分多用户环境下的可搜索加密方案是基于传统公钥密码或基于身份公钥密码系统,因此这类方案存在证书管理和密钥托管问题,且容易遭受内部关键词猜测攻击。该文结合公钥认证加密和代理重加密技术,提出一个高效的多用户环境下无证书认证可搜索加密方案。方案使用代理重加密技术对部分密文进行重加密处理,使得授权用户可以利用关键字生成陷门查询对应密文。在随机预言模型下,证明方案具有抵抗无证书公钥密码环境下两类攻击者的内部关键词猜测攻击的能力,且该方案的计算和通信效率优于同类方案。 相似文献
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代理重加密能够实现解密权限的转换,而鲁棒门限代理重加密(Threshold Proxy Re-Encryption,TPRE)不仅支持安全灵活的转化控制,而且支持转化密文的合法性验证.本文利用理想格上工具构造了一种TPRE方案,采用Shamir秘密共享实现门限控制,采用格上同态签名技术实现鲁棒性,可完全抗量子攻击.新方案与标准格上方案相比,密文尺寸小、密钥份额短、计算速度快;基于PRE和TPRE安全模型的差异,证明对TPRE的攻击多项式时间内可转化为对基础PRE方案的攻击,安全性可规约为R-LWE(Learning With Errors over Ring)困难假设;新方案适用于在去中心化环境中实现密文访问控制,可用于基于区块链网络的文件共享和多域网络快速互联等场景. 相似文献
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无证书公钥密码体制是在基于身份的公钥密码体制的基础上提出的新型公钥密码体制,它避免了密钥托管问题,也不需要使用公钥证书。代理重加密可以针对同一明文,实现不同用户公钥加密的密文之间的转换,在这个过程中半可信的代理者不能获得关于消息M的任何信息。文中将无证书公钥密码体制和代理重加密结合起来,介绍了一个基于双线性对的无证书代理重加密方案,该方案在标准模型下是抗适应性选择消息攻击的。 相似文献
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在移动社交网络中,为保证交友匹配过程中用户的隐私,提出多密钥混淆隐私保护方案.利用代理重加密技术,对用户密钥密文进行重新加密,实现了以扩充交友访问策略条件的交友匹配,并保证密文转换过程中用户的隐私不被泄露;利用随机密文组件加密技术,实现了对真实明文对应加密文件的信息隐藏,提高了攻击者的破解难度;利用数据摘要签名技术,解决了以往方案未考虑的多加密文件对应的文件解密问题.安全和实验分析表明,本文方案可以达到CPA(Chosen Plaintext Attack)安全,可以保证交友用户的隐私不被泄露,并且比既有的方案更有效. 相似文献
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Two different encryption schemes and Lagrange polynomial were used to construct a resplittable threshold multi-broker proxy re-encryption scheme on the lattice,namely the encryption in the ciphertext input and output side was different from the encryption in the re-encryption side which make the bound of noise was more relaxed.Threshold multi proxy not only ensure the safety of re-encryption key,but also ensure re-encryption scheme can still work even if the individual proxy could not provide normal services.The scheme is proven IND-UniRTPRE-CPA secure. 相似文献
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A ideal proxy re-encryption scheme has five features,such as one-way encryption,non-interaction,repeatability,controllability and verifiability.The existing schemes,however,have only two or three of the five features,which reduces the utility of them to some extent.For this,a new ciphertext-policy attribute-based proxy re-encryption (CP-ABPRE) scheme with the above five features was proposed.In the proposed scheme,the cloud proxy server could only re-encrypt the ciphertext specified by the delegator by using the re-encryption key,and resist the collusion attack between the user and the proxy satisfying the re-encryption sharing policy.Most of encryption and decryption were outsourced to cloud servers so that it reduced the computing burden on the user’s client.The security analysis show that the proposed scheme resists the selective chosen plaintext attack (SCPA). 相似文献
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Access control scheme is proposed for System Wide Information Management (SWIM) to address the problem of attribute revocation in practical applications. Based on the attribute based encryption (ABE), this scheme introduces the proxy re-encryption mechanism and key encrypting key (KEK) tree to realize fine-grained access control with attribute revocation. This paper defines the attributes according to the status quo of civil aviation. Compared with some other schemes proposed before, this scheme not only shortens the length of ciphertext (CT) and private key but also improves the efficiency of encryption and decryption. The scheme can resist collusion attacks and ensure the security of data in SWIM. 相似文献