All watermarks are shared into shadow images using VCS(Visual Cryptography Scheme). Only one specific shadow (as a new watermark) is embedded into the host signal and the other ones are distributed to every user in ea...All watermarks are shared into shadow images using VCS(Visual Cryptography Scheme). Only one specific shadow (as a new watermark) is embedded into the host signal and the other ones are distributed to every user in each group as a key. In the watermarking extraction procedure, users in different group can obtain different watermark by combining their shadows with the extracted one from the watermarked signal. Analysis and experimental results show that the new watermarking method is novel, secure and robust.展开更多
All-digital carrier synchronization strategies and algorithms for space-time block coding (STBC) orthogonal frequency division multiplexing (OFDM) are proposed in this paper. In our scheme, the continuous pilots (CP) ...All-digital carrier synchronization strategies and algorithms for space-time block coding (STBC) orthogonal frequency division multiplexing (OFDM) are proposed in this paper. In our scheme, the continuous pilots (CP) are saved, and the complexity of carrier synchronization is reduced significantly by dividing the process into three steps. The coarse carrier synchronization and the fine carrier synchronization algorithms are investigated and analyzed in detail. Simulations show that the carrier can be locked into tracking mode quickly, and the residual frequency error satisfies the system requirement in both stationary and mobile environments.展开更多
We propose a class of Quantum Secret Sharing (QSS) scheme based onmulti-particle entanglement. The eavesdropping analysis shows that the scheme is secure. Itsefficiency is 100% in principle. That is, one multi-particl...We propose a class of Quantum Secret Sharing (QSS) scheme based onmulti-particle entanglement. The eavesdropping analysis shows that the scheme is secure. Itsefficiency is 100% in principle. That is, one multi-particle entanglement can be used to share a bitof classical key among the parties. As a result, it is resource saving. The protocol can also beadjusted to split a classical secret message directly. The implementation of it is relativelyapplicable.展开更多
Abe et al. proposed the methodology of ring signature (RS) design in 2002 andshowed how to construct RS with a mixture of public keys based on factorization and/or discretelogarithms. Their methodology cannot be appli...Abe et al. proposed the methodology of ring signature (RS) design in 2002 andshowed how to construct RS with a mixture of public keys based on factorization and/or discretelogarithms. Their methodology cannot be applied to knowledge signatures (KS) using the Fiat-Shamirheuristic and cut-and-choose techniques, for instance, the Goldreich KS. This paper presents a moregeneral construction of RS from various public keys if there exists a secure signature using such apublic key and an efficient algorithm to forge the relation to be checked if the challenges in sucha signature are known in advance. The paper shows how to construct RS based on the graph isomorphismproblem (GIP). Although it is unknown whether or not GIP is NP-Complete, there are no knownarguments that it can be solved even in the quantum computation model. Hence, the scheme has abetter security basis and it is plausibly secure against quantum adversaries.展开更多
According to the analysis of meteor burst communication (MBC) mechanism, a model of signal processing based on the structure of data frame is suggested for adaptive modulation and coding (AMC) of MBC system in this pa...According to the analysis of meteor burst communication (MBC) mechanism, a model of signal processing based on the structure of data frame is suggested for adaptive modulation and coding (AMC) of MBC system in this paper. There are two distinct modes of operation for signal processing: acquisition and tracking. The acquisition mode is a training period to initialize the channel estimation by frame header. The tracking mode is jointly to equalize payload data and to trace channel, where the principle of per-survivor processing (PSP) for maximum likelihood sequence detection (MLSD) is performed. A suboptimal method called D-PSP is adopted to save the computational time and memory size, which agrees with the slow-fading characteristic of meteor channel and makes the MLSD possible for adaptive modulation and coding of MBC system. Computer simulation results are included to support our development.展开更多
In this paper two Quantum Key Distribution(QKD)protocols are proposed,which combined BB84 protocoland EPR protocol subtly.In our protocols,entangled particles and non-orthogonal particles are mixed together and trans-...In this paper two Quantum Key Distribution(QKD)protocols are proposed,which combined BB84 protocoland EPR protocol subtly.In our protocols,entangled particles and non-orthogonal particles are mixed together and trans-mitted in the quantum channel.They play different roles respectively,and their physical characters are fully exploited.As a result,the efficiency of QKD is improved and identity authentication is added to the QKD procedure.展开更多
基金Supported by the National Natural Science Foundation of China (No.90204017, 60373059)National 973 Project (G1999035805) ISN Open Foundation
文摘All watermarks are shared into shadow images using VCS(Visual Cryptography Scheme). Only one specific shadow (as a new watermark) is embedded into the host signal and the other ones are distributed to every user in each group as a key. In the watermarking extraction procedure, users in different group can obtain different watermark by combining their shadows with the extracted one from the watermarked signal. Analysis and experimental results show that the new watermarking method is novel, secure and robust.
文摘All-digital carrier synchronization strategies and algorithms for space-time block coding (STBC) orthogonal frequency division multiplexing (OFDM) are proposed in this paper. In our scheme, the continuous pilots (CP) are saved, and the complexity of carrier synchronization is reduced significantly by dividing the process into three steps. The coarse carrier synchronization and the fine carrier synchronization algorithms are investigated and analyzed in detail. Simulations show that the carrier can be locked into tracking mode quickly, and the residual frequency error satisfies the system requirement in both stationary and mobile environments.
基金This work is supported by the National Natural Science Foundation of China (No.60373059) the National Laboratory for Modern Communications Science Foundationof China (No. 51436020103DZ4001) National Research Foundation for the Doctoral Program of Hig
文摘We propose a class of Quantum Secret Sharing (QSS) scheme based onmulti-particle entanglement. The eavesdropping analysis shows that the scheme is secure. Itsefficiency is 100% in principle. That is, one multi-particle entanglement can be used to share a bitof classical key among the parties. As a result, it is resource saving. The protocol can also beadjusted to split a classical secret message directly. The implementation of it is relativelyapplicable.
文摘Abe et al. proposed the methodology of ring signature (RS) design in 2002 andshowed how to construct RS with a mixture of public keys based on factorization and/or discretelogarithms. Their methodology cannot be applied to knowledge signatures (KS) using the Fiat-Shamirheuristic and cut-and-choose techniques, for instance, the Goldreich KS. This paper presents a moregeneral construction of RS from various public keys if there exists a secure signature using such apublic key and an efficient algorithm to forge the relation to be checked if the challenges in sucha signature are known in advance. The paper shows how to construct RS based on the graph isomorphismproblem (GIP). Although it is unknown whether or not GIP is NP-Complete, there are no knownarguments that it can be solved even in the quantum computation model. Hence, the scheme has abetter security basis and it is plausibly secure against quantum adversaries.
文摘According to the analysis of meteor burst communication (MBC) mechanism, a model of signal processing based on the structure of data frame is suggested for adaptive modulation and coding (AMC) of MBC system in this paper. There are two distinct modes of operation for signal processing: acquisition and tracking. The acquisition mode is a training period to initialize the channel estimation by frame header. The tracking mode is jointly to equalize payload data and to trace channel, where the principle of per-survivor processing (PSP) for maximum likelihood sequence detection (MLSD) is performed. A suboptimal method called D-PSP is adopted to save the computational time and memory size, which agrees with the slow-fading characteristic of meteor channel and makes the MLSD possible for adaptive modulation and coding of MBC system. Computer simulation results are included to support our development.
文摘In this paper two Quantum Key Distribution(QKD)protocols are proposed,which combined BB84 protocoland EPR protocol subtly.In our protocols,entangled particles and non-orthogonal particles are mixed together and trans-mitted in the quantum channel.They play different roles respectively,and their physical characters are fully exploited.As a result,the efficiency of QKD is improved and identity authentication is added to the QKD procedure.
