Due to the mobility of users in an organization,inclusion of dynamic attributes such as time and location becomes the major challenge in Ciphertext-Policy Attribute-Based Encryption(CP-ABE).By considering this challen...Due to the mobility of users in an organization,inclusion of dynamic attributes such as time and location becomes the major challenge in Ciphertext-Policy Attribute-Based Encryption(CP-ABE).By considering this challenge;we focus to present dynamic time and location information in CP-ABE with mul-ti-authorization.Atfirst,along with the set of attributes of the users,their corre-sponding location is also embedded.Geohash is used to encode the latitude and longitude of the user’s position.Then,decrypt time period and access time period of users are defined using the new time tree(NTT)structure.The NTT sets the encrypted duration of the encrypted data and the valid access time of the private key on the data user’s private key.Besides,single authorization of attribute authority(AA)is extended as multi authorization for enhancing the effectiveness of key generation.Simulation results depict that the proposed CP-ABE achieves better encryption time,decryption time,security level and memory usage.Namely,encryption time and decryption time of the proposed CP-ABE are reduced to 19%and 16%than that of existing CP-ABE scheme.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
TrustedRBAC is a scalable, decentralized trust-management and access control mechanism for systems that span multiple autonomous domains. We utilize X.509 attri- bute certificates to define trust domains, roles to def...TrustedRBAC is a scalable, decentralized trust-management and access control mechanism for systems that span multiple autonomous domains. We utilize X.509 attri- bute certificates to define trust domains, roles to define controlled activities, and role delegation across domains to represent permissions to these activities. This paper describes the TrustedRBAC model and its scalable design and implementation.展开更多
针对医疗隐私数据在存储和传输交互过程中易泄露的问题,提出一种基于多授权中心协同的数据保护方案(Multi-Authorization Collaborative Data Protection Scheme,MACDPS)。该方案利用区块链智能合约技术,由多组区块节点构成多属性授权中...针对医疗隐私数据在存储和传输交互过程中易泄露的问题,提出一种基于多授权中心协同的数据保护方案(Multi-Authorization Collaborative Data Protection Scheme,MACDPS)。该方案利用区块链智能合约技术,由多组区块节点构成多属性授权中心,实现公共参数和主密钥的安全生成,解决单一授权中心权限过大可能引发的用户密钥泄露问题。采用基于属性的加密算法和对称加密算法对密钥和隐私数据进行双重加密,并保存于云存储服务器中,以确保隐私数据的细粒度访问和机密性。实验与安全性分析结果表明,所提方案能够保证密钥的机密性,实现了患者隐私数据的有效存储和抗泄露,具有高效的传输能力以及较强的安全性。展开更多
文摘Due to the mobility of users in an organization,inclusion of dynamic attributes such as time and location becomes the major challenge in Ciphertext-Policy Attribute-Based Encryption(CP-ABE).By considering this challenge;we focus to present dynamic time and location information in CP-ABE with mul-ti-authorization.Atfirst,along with the set of attributes of the users,their corre-sponding location is also embedded.Geohash is used to encode the latitude and longitude of the user’s position.Then,decrypt time period and access time period of users are defined using the new time tree(NTT)structure.The NTT sets the encrypted duration of the encrypted data and the valid access time of the private key on the data user’s private key.Besides,single authorization of attribute authority(AA)is extended as multi authorization for enhancing the effectiveness of key generation.Simulation results depict that the proposed CP-ABE achieves better encryption time,decryption time,security level and memory usage.Namely,encryption time and decryption time of the proposed CP-ABE are reduced to 19%and 16%than that of existing CP-ABE scheme.
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TrustedRBAC is a scalable, decentralized trust-management and access control mechanism for systems that span multiple autonomous domains. We utilize X.509 attri- bute certificates to define trust domains, roles to define controlled activities, and role delegation across domains to represent permissions to these activities. This paper describes the TrustedRBAC model and its scalable design and implementation.
文摘针对医疗隐私数据在存储和传输交互过程中易泄露的问题,提出一种基于多授权中心协同的数据保护方案(Multi-Authorization Collaborative Data Protection Scheme,MACDPS)。该方案利用区块链智能合约技术,由多组区块节点构成多属性授权中心,实现公共参数和主密钥的安全生成,解决单一授权中心权限过大可能引发的用户密钥泄露问题。采用基于属性的加密算法和对称加密算法对密钥和隐私数据进行双重加密,并保存于云存储服务器中,以确保隐私数据的细粒度访问和机密性。实验与安全性分析结果表明,所提方案能够保证密钥的机密性,实现了患者隐私数据的有效存储和抗泄露,具有高效的传输能力以及较强的安全性。
