Distributed information systems require complex access control which depends upon attributes of protected data and access policies.Traditionally,to enforce the access control,a file server is used to store all data an...Distributed information systems require complex access control which depends upon attributes of protected data and access policies.Traditionally,to enforce the access control,a file server is used to store all data and act as a reference to check the user.Apparently,the drawback of this system is that the security is based on the file server and the data are stored in plaintext.Attribute-based encryption(ABE) is introduced first by Sahai and Waters and can enable an access control mechanism over encrypted data by specifying the users’ attributes. According to this mechanism,even though the file server is compromised,we can still keep the security of the data. Besides the access control,user may be deprived of the ability in some situation,for example paying TV.More previous ABE constructions are proven secure in the selective model of security that attacker must announce the target he intends to attack before seeing the public parameters.And few of previous ABE constructions realize revocation of the users’ key.This paper presents an ABE scheme that supports revocation and has full security in adaptive model.We adapt the dual system encryption technique recently introduced by Waters to ABE to realize full security.展开更多
This study deals with the dynamic property of threshold cryptosystem. A dynamic threshold cryptosystem allows the sender to choose the authorized decryption group and the threshold value for each message dynamically. ...This study deals with the dynamic property of threshold cryptosystem. A dynamic threshold cryptosystem allows the sender to choose the authorized decryption group and the threshold value for each message dynamically. We first introduce an identity based dynamic threshold cryptosystem, and then use the CanettiHalevi-Katz(CHK) transformation to transform it into a fully secure system in the traditional public key setting.Finally, the elegant dual system encryption technique is applied to constructing a fully secure dynamic threshold cryptosystem with adaptive security.展开更多
In this paper,we show how to use the dual techniques in the subgroups to give a secure identity-based broadcast encryption(IBBE) scheme with constant-size ciphertexts. Our scheme achieves the full security(adaptive se...In this paper,we show how to use the dual techniques in the subgroups to give a secure identity-based broadcast encryption(IBBE) scheme with constant-size ciphertexts. Our scheme achieves the full security(adaptive security) under three static(i.e. non q-based) assumptions. It is worth noting that only recently Waters gives a short ciphertext broadcast encryption system that is even adaptively secure under the simple assumptions. One feature of our methodology is that it is relatively simple to leverage our techniques to get adaptive security.展开更多
基金the National Natural Science Foundation of China(No.60972034)
文摘Distributed information systems require complex access control which depends upon attributes of protected data and access policies.Traditionally,to enforce the access control,a file server is used to store all data and act as a reference to check the user.Apparently,the drawback of this system is that the security is based on the file server and the data are stored in plaintext.Attribute-based encryption(ABE) is introduced first by Sahai and Waters and can enable an access control mechanism over encrypted data by specifying the users’ attributes. According to this mechanism,even though the file server is compromised,we can still keep the security of the data. Besides the access control,user may be deprived of the ability in some situation,for example paying TV.More previous ABE constructions are proven secure in the selective model of security that attacker must announce the target he intends to attack before seeing the public parameters.And few of previous ABE constructions realize revocation of the users’ key.This paper presents an ABE scheme that supports revocation and has full security in adaptive model.We adapt the dual system encryption technique recently introduced by Waters to ABE to realize full security.
基金the National Natural Science Foundation of China(Nos.61202023,60903189 and 61133014)
文摘This study deals with the dynamic property of threshold cryptosystem. A dynamic threshold cryptosystem allows the sender to choose the authorized decryption group and the threshold value for each message dynamically. We first introduce an identity based dynamic threshold cryptosystem, and then use the CanettiHalevi-Katz(CHK) transformation to transform it into a fully secure system in the traditional public key setting.Finally, the elegant dual system encryption technique is applied to constructing a fully secure dynamic threshold cryptosystem with adaptive security.
基金supported by the Nature Science Foundation of China under grant 60970119, 60803149the National Basic Research Program of China(973) under grant 2007CB311201
文摘In this paper,we show how to use the dual techniques in the subgroups to give a secure identity-based broadcast encryption(IBBE) scheme with constant-size ciphertexts. Our scheme achieves the full security(adaptive security) under three static(i.e. non q-based) assumptions. It is worth noting that only recently Waters gives a short ciphertext broadcast encryption system that is even adaptively secure under the simple assumptions. One feature of our methodology is that it is relatively simple to leverage our techniques to get adaptive security.
