The cloud storage service cannot be completely trusted because of the separation of data management and ownership, leading to the difficulty of data privacy protection. In order to protect the privacy of data on untru...The cloud storage service cannot be completely trusted because of the separation of data management and ownership, leading to the difficulty of data privacy protection. In order to protect the privacy of data on untrusted servers of cloud storage, a novel multi-authority access control scheme without a trustworthy central authority has been proposed based on CP-ABE for cloud storage systems, called non-centered multi-authority proxy re-encryption based on the cipher-text policy attribute-based encryption(NC-MACPABE). NC-MACPABE optimizes the weighted access structure(WAS) allowing different levels of operation on the same file in cloud storage system. The concept of identity dyeing is introduced to improve the users' information privacy further. The re-encryption algorithm is improved in the scheme so that the data owner can revoke user's access right in a more flexible way. The scheme is proved to be secure. And the experimental results also show that removing the central authority can resolve the existing performance bottleneck in the multi-authority architecture with a central authority, which significantly improves user experience when a large number of users apply for accesses to the cloud storage system at the same time.展开更多
The dissociation between data management and data ownership makes it difficult to protect data security and privacy in cloud storage systems.Traditional encryption technologies are not suitable for data protection in ...The dissociation between data management and data ownership makes it difficult to protect data security and privacy in cloud storage systems.Traditional encryption technologies are not suitable for data protection in cloud storage systems.A novel multi-authority proxy re-encryption mechanism based on ciphertext-policy attribute-based encryption（MPRE-CPABE） is proposed for cloud storage systems.MPRE-CPABE requires data owner to split each file into two blocks,one big block and one small block.The small block is used to encrypt the big one as the private key,and then the encrypted big block will be uploaded to the cloud storage system.Even if the uploaded big block of file is stolen,illegal users cannot get the complete information of the file easily.Ciphertext-policy attribute-based encryption（CPABE）is always criticized for its heavy overload and insecure issues when distributing keys or revoking user＇s access right.MPRE-CPABE applies CPABE to the multi-authority cloud storage system,and solves the above issues.The weighted access structure（WAS） is proposed to support a variety of fine-grained threshold access control policy in multi-authority environments,and reduce the computational cost of key distribution.Meanwhile,MPRE-CPABE uses proxy re-encryption to reduce the computational cost of access revocation.Experiments are implemented on platforms of Ubuntu and CloudSim.Experimental results show that MPRE-CPABE can greatly reduce the computational cost of the generation of key components and the revocation of user＇s access right.MPRE-CPABE is also proved secure under the security model of decisional bilinear Diffie-Hellman（DBDH）.展开更多
有越来越多的用户选择云为其进行存储、运算、共享等数据处理工作,因此云端数据量与日俱增,其中不乏敏感数据和隐私信息.如何对用户托管于云端的数据进行授权管理,保证数据机密性、访问授权有效性等至关重要.为此,提出一种基于代理重加...有越来越多的用户选择云为其进行存储、运算、共享等数据处理工作,因此云端数据量与日俱增,其中不乏敏感数据和隐私信息.如何对用户托管于云端的数据进行授权管理,保证数据机密性、访问授权有效性等至关重要.为此,提出一种基于代理重加密(proxy re-encryption,简称PRE)的云端数据访问授权的确定性更新方案(proxy re-encryption based assured update scheme of authorization,简称PAUA).首先将提出PAUA方案的前提假设和目标,其次论述系统模型和算法,最后对PAUA进行讨论和分析.PAUA方案将减轻用户在数据共享时的计算量,同时将重加密密钥进行分割管理,实现授权变更时,密钥的确定性更新.展开更多
数据的机密性是云存储环境下的难点问题,基于密文的访问控制技术是解决该问题的重要思路,在目前的基于密文的访问控制技术中,数据的高安全需求和频繁的策略更新使得数据拥有者(data owner,DO)端的权限更新代价过高,进而严重制约了系统...数据的机密性是云存储环境下的难点问题,基于密文的访问控制技术是解决该问题的重要思路,在目前的基于密文的访问控制技术中,数据的高安全需求和频繁的策略更新使得数据拥有者(data owner,DO)端的权限更新代价过高,进而严重制约了系统的整体效率.针对此问题,提出一种适用于云存储动态策略的密文访问控制方法(cryptographic access control strategy for dynamic policy,CACDP),该方法提出了一种基于二叉Trie树的密钥管理机制,在此基础之上利用基于ELGamal的代理重加密机制和双层加密策略,将密钥和数据更新的部分开销转移到云端以减少DO权限管理负担,提高DO的处理效率.最后通过实验验证了该方案有效降低了策略更新为DO带来的性能开销.展开更多
基金Projects(61472192,61202004)supported by the National Natural Science Foundation of ChinaProject(14KJB520014)supported by the Natural Science Fund of Higher Education of Jiangsu Province,China
文摘The cloud storage service cannot be completely trusted because of the separation of data management and ownership, leading to the difficulty of data privacy protection. In order to protect the privacy of data on untrusted servers of cloud storage, a novel multi-authority access control scheme without a trustworthy central authority has been proposed based on CP-ABE for cloud storage systems, called non-centered multi-authority proxy re-encryption based on the cipher-text policy attribute-based encryption(NC-MACPABE). NC-MACPABE optimizes the weighted access structure(WAS) allowing different levels of operation on the same file in cloud storage system. The concept of identity dyeing is introduced to improve the users' information privacy further. The re-encryption algorithm is improved in the scheme so that the data owner can revoke user's access right in a more flexible way. The scheme is proved to be secure. And the experimental results also show that removing the central authority can resolve the existing performance bottleneck in the multi-authority architecture with a central authority, which significantly improves user experience when a large number of users apply for accesses to the cloud storage system at the same time.
基金supported by the National Natural Science Foundation of China(6120200461472192)+1 种基金the Special Fund for Fast Sharing of Science Paper in Net Era by CSTD(2013116)the Natural Science Fund of Higher Education of Jiangsu Province(14KJB520014)
文摘The dissociation between data management and data ownership makes it difficult to protect data security and privacy in cloud storage systems.Traditional encryption technologies are not suitable for data protection in cloud storage systems.A novel multi-authority proxy re-encryption mechanism based on ciphertext-policy attribute-based encryption（MPRE-CPABE） is proposed for cloud storage systems.MPRE-CPABE requires data owner to split each file into two blocks,one big block and one small block.The small block is used to encrypt the big one as the private key,and then the encrypted big block will be uploaded to the cloud storage system.Even if the uploaded big block of file is stolen,illegal users cannot get the complete information of the file easily.Ciphertext-policy attribute-based encryption（CPABE）is always criticized for its heavy overload and insecure issues when distributing keys or revoking user＇s access right.MPRE-CPABE applies CPABE to the multi-authority cloud storage system,and solves the above issues.The weighted access structure（WAS） is proposed to support a variety of fine-grained threshold access control policy in multi-authority environments,and reduce the computational cost of key distribution.Meanwhile,MPRE-CPABE uses proxy re-encryption to reduce the computational cost of access revocation.Experiments are implemented on platforms of Ubuntu and CloudSim.Experimental results show that MPRE-CPABE can greatly reduce the computational cost of the generation of key components and the revocation of user＇s access right.MPRE-CPABE is also proved secure under the security model of decisional bilinear Diffie-Hellman（DBDH）.
文摘有越来越多的用户选择云为其进行存储、运算、共享等数据处理工作,因此云端数据量与日俱增,其中不乏敏感数据和隐私信息.如何对用户托管于云端的数据进行授权管理,保证数据机密性、访问授权有效性等至关重要.为此,提出一种基于代理重加密(proxy re-encryption,简称PRE)的云端数据访问授权的确定性更新方案(proxy re-encryption based assured update scheme of authorization,简称PAUA).首先将提出PAUA方案的前提假设和目标,其次论述系统模型和算法,最后对PAUA进行讨论和分析.PAUA方案将减轻用户在数据共享时的计算量,同时将重加密密钥进行分割管理,实现授权变更时,密钥的确定性更新.
文摘数据的机密性是云存储环境下的难点问题,基于密文的访问控制技术是解决该问题的重要思路,在目前的基于密文的访问控制技术中,数据的高安全需求和频繁的策略更新使得数据拥有者(data owner,DO)端的权限更新代价过高,进而严重制约了系统的整体效率.针对此问题,提出一种适用于云存储动态策略的密文访问控制方法(cryptographic access control strategy for dynamic policy,CACDP),该方法提出了一种基于二叉Trie树的密钥管理机制,在此基础之上利用基于ELGamal的代理重加密机制和双层加密策略,将密钥和数据更新的部分开销转移到云端以减少DO权限管理负担,提高DO的处理效率.最后通过实验验证了该方案有效降低了策略更新为DO带来的性能开销.
