For the applied limitation of the existing threshold decryption schemes based on the(t,n) structure, an identity-based threshold decryption scheme which can be applied on the access structure is proposed through desig...For the applied limitation of the existing threshold decryption schemes based on the(t,n) structure, an identity-based threshold decryption scheme which can be applied on the access structure is proposed through designing a special distribution algorithm of the private key shares.The generation and distribution of private key shares,the encryption,the decryption and the combination are introduced in detail.The validity and security of the scheme are proved and analyzed.Comparisons with the existing schemes show that the proposed scheme is more flexible.展开更多
Random access is the necessary process to establish the wireless link between the user equipment(UE)and network.The performance of the random access directly affects the performance of the network.In this work,we prop...Random access is the necessary process to establish the wireless link between the user equipment(UE)and network.The performance of the random access directly affects the performance of the network.In this work,we propose a method on the basis of the existing alternatives.In this method,we estimate the system load in advance to adjust the number of terminals.An access threshold is set to control the number of terminals which want to access the base station at an acceptable level.At the same time,we have an improvement on the existing power climbing strategy.We suppose that the power ramping is not always necessary for the re-access.And the selection of power ramping steps is studied in this paper.Simulations based on MATLAB are employed to evaluate the effectiveness of the proposed solution and to make comparisons with existing alternatives.展开更多
With the massive diffusion of cloud computing, more and more sensitive data is being centralized into the cloud for sharing, which brings forth new challenges for the security and privacy of outsourced data. To addres...With the massive diffusion of cloud computing, more and more sensitive data is being centralized into the cloud for sharing, which brings forth new challenges for the security and privacy of outsourced data. To address these challenges, the server-aided access control(SAAC) system was proposed. The SAAC system builds upon a variant of conditional proxy re-encryption(CPRE) named threshold conditional proxy re-encryption(TCPRE). In TCPRE, t out of n proxies can re-encrypt ciphertexts(satisfying some specified conditions) for the delegator(while up to t-1 proxies cannot), and the correctness of the re-encrypted ciphertexts can be publicly verified. Both features guarantee the trust and reliability on the proxies deployed in the SAAC system. The security models for TCPRE were formalized, several TCPRE constructions were proposed and that our final scheme was secure against chosen-ciphertext attacks was proved.展开更多
分析了两种有效的可验证秘密共享方案:Feldman s VSS方案和Pedersen s VSS方案。但是它们都是门限方案,当推广到一般接入结构时,效率都很低。为此,提出了一个一般接入结构上的可验证秘密共享方案。参与者的共享由秘密分发者随机生成,采...分析了两种有效的可验证秘密共享方案:Feldman s VSS方案和Pedersen s VSS方案。但是它们都是门限方案,当推广到一般接入结构时,效率都很低。为此,提出了一个一般接入结构上的可验证秘密共享方案。参与者的共享由秘密分发者随机生成,采用秘密信道发送。每个授权子集拥有一个的公开信息,通过公开的信息,参与者能够验证属于自己份额的共享的有效性。该方案具有两种形式:一种是计算安全的,另一种是无条件安全的。其安全性分别等同于Feldman sVSS方案和Pedersen sVSS方案,但在相同的安全级别下,新方案更有效。展开更多
基金the National Natural Science Foundation of China(No.60374066)
文摘For the applied limitation of the existing threshold decryption schemes based on the(t,n) structure, an identity-based threshold decryption scheme which can be applied on the access structure is proposed through designing a special distribution algorithm of the private key shares.The generation and distribution of private key shares,the encryption,the decryption and the combination are introduced in detail.The validity and security of the scheme are proved and analyzed.Comparisons with the existing schemes show that the proposed scheme is more flexible.
基金partly supported by the Research of LTE Layer 2 and Smallcell Technology Tracking under Grant No.2013GFW-0005
文摘Random access is the necessary process to establish the wireless link between the user equipment(UE)and network.The performance of the random access directly affects the performance of the network.In this work,we propose a method on the basis of the existing alternatives.In this method,we estimate the system load in advance to adjust the number of terminals.An access threshold is set to control the number of terminals which want to access the base station at an acceptable level.At the same time,we have an improvement on the existing power climbing strategy.We suppose that the power ramping is not always necessary for the re-access.And the selection of power ramping steps is studied in this paper.Simulations based on MATLAB are employed to evaluate the effectiveness of the proposed solution and to make comparisons with existing alternatives.
基金The National Natural Science Foundation of China(No.61272413,No.61472165)
文摘With the massive diffusion of cloud computing, more and more sensitive data is being centralized into the cloud for sharing, which brings forth new challenges for the security and privacy of outsourced data. To address these challenges, the server-aided access control(SAAC) system was proposed. The SAAC system builds upon a variant of conditional proxy re-encryption(CPRE) named threshold conditional proxy re-encryption(TCPRE). In TCPRE, t out of n proxies can re-encrypt ciphertexts(satisfying some specified conditions) for the delegator(while up to t-1 proxies cannot), and the correctness of the re-encrypted ciphertexts can be publicly verified. Both features guarantee the trust and reliability on the proxies deployed in the SAAC system. The security models for TCPRE were formalized, several TCPRE constructions were proposed and that our final scheme was secure against chosen-ciphertext attacks was proved.
文摘分析了两种有效的可验证秘密共享方案:Feldman s VSS方案和Pedersen s VSS方案。但是它们都是门限方案,当推广到一般接入结构时,效率都很低。为此,提出了一个一般接入结构上的可验证秘密共享方案。参与者的共享由秘密分发者随机生成,采用秘密信道发送。每个授权子集拥有一个的公开信息,通过公开的信息,参与者能够验证属于自己份额的共享的有效性。该方案具有两种形式:一种是计算安全的,另一种是无条件安全的。其安全性分别等同于Feldman sVSS方案和Pedersen sVSS方案,但在相同的安全级别下,新方案更有效。
