Based on the authentication tests and the strand space model, the robust email protocol with perfect forward secrecy is formally analyzed, and the security shortcomings of the protocol is pointed out. Meanwhile, the m...Based on the authentication tests and the strand space model, the robust email protocol with perfect forward secrecy is formally analyzed, and the security shortcomings of the protocol is pointed out. Meanwhile, the man-in-the-middle attack to the protocol is given, where the attacker forges the messages in the receiving phase to cheat the two communication parties and makes them share the wrong session keys with him. Therefore, the protocol is not ensured to provide perfect forward secrecy. In order to overcome the above security shortcomings, an advanced email protocol is proposed, where the corresponding signatures in the receiving phase of the protocol are added to overcome the man-in-the-middle attack and ensure to provide perfect forward secrecy. Finally, the proposed advanced email protocol is formally analyzed with the authentication tests and the strand space model, and it is proved to be secure in authentication of the email sender, the recipient and the server. Therefore, the proposed advanced email protocol can really provide perfect forward secrecy.展开更多
With the growing trend toward using cloud storage,the problem of efficiently checking and proving data integrity needs more consideration.Many cryptography and security schemes,such as PDP(Provable Data Possession) an...With the growing trend toward using cloud storage,the problem of efficiently checking and proving data integrity needs more consideration.Many cryptography and security schemes,such as PDP(Provable Data Possession) and POR(Proofs of Retrievability) were proposed for this problem.Although many efficient schemes for static data have been constructed,only a few dynamic schemes exist,such as DPDP(Dynamic Provable Data Possession).But the DPDP scheme falls short when updates are not proportional to a fixed block size.The FlexList-based Dynamic Provable Data Possession(FlexDPDP) was an optimized scheme for DPDP.However,the update operations(insertion,remove,modification)in Flex DPDP scheme only apply to single node at a time,while multiple consecutive nodes operation is more common in practice.To solve this problem,we propose optimized algorithms for multiple consecutive nodes,which including MultiNodes Insert and Verification,MultiNodes Remove and Verification,MultiNodes Modify and Verification.The cost of our optimized algorithms is also analyzed.For m consecutive nodes,an insertion takes O(m) + O(log N) + O(log m),where N is the number of leaf nodes of FlexList,a remove takes O(log/V),and a modification is the same as the original algorithm.Finally,we compare the optimized algorithms with original FlexList through experiences,and the results show that our scheme has the higher efficiency of time and space.展开更多
Authentication is the basis of the security of IEEE 802.11i standard. The authentication process in 802.11i involves two important protocols： a 4-way handshake and a group key handshake. A formal analysis of authenti...Authentication is the basis of the security of IEEE 802.11i standard. The authentication process in 802.11i involves two important protocols： a 4-way handshake and a group key handshake. A formal analysis of authentication in 802.11i is given via a belief multisets formalism. The analysis shows that the 4-way handshake and the group key handshake may provide satisfactory mutual authentication, key management, and issue of a new group temporal key from an access point to a user device, under the guarantee of mutual possession of a confidential palrwise master key. The analysis also shows that there exists a denial of service attack in the 4-way handshake and some seeming redundancies are useful in the protocol implementation.展开更多
基金The Natural Science Foundation of Jiangsu Province(No.BK2006108)
文摘Based on the authentication tests and the strand space model, the robust email protocol with perfect forward secrecy is formally analyzed, and the security shortcomings of the protocol is pointed out. Meanwhile, the man-in-the-middle attack to the protocol is given, where the attacker forges the messages in the receiving phase to cheat the two communication parties and makes them share the wrong session keys with him. Therefore, the protocol is not ensured to provide perfect forward secrecy. In order to overcome the above security shortcomings, an advanced email protocol is proposed, where the corresponding signatures in the receiving phase of the protocol are added to overcome the man-in-the-middle attack and ensure to provide perfect forward secrecy. Finally, the proposed advanced email protocol is formally analyzed with the authentication tests and the strand space model, and it is proved to be secure in authentication of the email sender, the recipient and the server. Therefore, the proposed advanced email protocol can really provide perfect forward secrecy.
基金supported in part by the National Natural Science Foundation of China under Grant No.61440014&&No.61300196the Liaoning Province Doctor Startup Fundunder Grant No.20141012+2 种基金the Liaoning Province Science and Technology Projects under Grant No.2013217004the Shenyang Province Science and Technology Projects under Grant Nothe Fundamental Research Funds for the Central Universities under Grant No.N130317002 and No.N130317003
文摘With the growing trend toward using cloud storage,the problem of efficiently checking and proving data integrity needs more consideration.Many cryptography and security schemes,such as PDP(Provable Data Possession) and POR(Proofs of Retrievability) were proposed for this problem.Although many efficient schemes for static data have been constructed,only a few dynamic schemes exist,such as DPDP(Dynamic Provable Data Possession).But the DPDP scheme falls short when updates are not proportional to a fixed block size.The FlexList-based Dynamic Provable Data Possession(FlexDPDP) was an optimized scheme for DPDP.However,the update operations(insertion,remove,modification)in Flex DPDP scheme only apply to single node at a time,while multiple consecutive nodes operation is more common in practice.To solve this problem,we propose optimized algorithms for multiple consecutive nodes,which including MultiNodes Insert and Verification,MultiNodes Remove and Verification,MultiNodes Modify and Verification.The cost of our optimized algorithms is also analyzed.For m consecutive nodes,an insertion takes O(m) + O(log N) + O(log m),where N is the number of leaf nodes of FlexList,a remove takes O(log/V),and a modification is the same as the original algorithm.Finally,we compare the optimized algorithms with original FlexList through experiences,and the results show that our scheme has the higher efficiency of time and space.
基金the National High Technology Research and Development Program(863)of China(No.2006AA01Z422)the National Natural Science Foundation of China(Nos.60573030,90704004)
文摘Authentication is the basis of the security of IEEE 802.11i standard. The authentication process in 802.11i involves two important protocols： a 4-way handshake and a group key handshake. A formal analysis of authentication in 802.11i is given via a belief multisets formalism. The analysis shows that the 4-way handshake and the group key handshake may provide satisfactory mutual authentication, key management, and issue of a new group temporal key from an access point to a user device, under the guarantee of mutual possession of a confidential palrwise master key. The analysis also shows that there exists a denial of service attack in the 4-way handshake and some seeming redundancies are useful in the protocol implementation.
