In the area of secure Web information system, mutual authentication and key agreement are essential between Web clients and servers. An efficient certificateless authenticated key agreement protocol for Web client/ser...In the area of secure Web information system, mutual authentication and key agreement are essential between Web clients and servers. An efficient certificateless authenticated key agreement protocol for Web client/server setting is proposed, which uses pairings on certain elliptic curves. We show that the newly proposed key agreement protocol is practical and of great efficiency, meanwhile, it satisfies every desired security require ments for key agreement protocols.展开更多
Signcryption is a cryptographic primitive that performs signature and encryption simultaneously, at lower computational costs and communication overheads than the signature-then- encryption approach. In this paper, we...Signcryption is a cryptographic primitive that performs signature and encryption simultaneously, at lower computational costs and communication overheads than the signature-then- encryption approach. In this paper, we propose an efficient multi-recipient signcryption scheme based on the bilinear pairings, which broadcasts a message to multiple users in a secure and authenticated manner. We prove its semantic security and unforgeability under the Gap Diffie-Hellman problem assumption in the random oracle model. The proposed scheme is more efficient than re-signcrypting a message n times using a signcryption scheme in terms of computational costs and communication overheads.展开更多
We argue that traditional identity-based systems from pairings seem unsuitable for designing group signature schemes due to the problem of key escrow. In this paper we first propose new ID-based public key systems wit...We argue that traditional identity-based systems from pairings seem unsuitable for designing group signature schemes due to the problem of key escrow. In this paper we first propose new ID-based public key systems without trusted PKG (Private Key Generator) from bilinear pairings. In our new ID-based systems, if the dishonest PKG impersonates an honest user to communicate with others, the user can provide a proof of treachery of the PKG afterwards, which is similar to certificate-based systems. Therefore, our systems reach the Girault’s trusted level 3. We then propose a group signature scheme under the new ID-based systems, the security and performance of which rely on the new systems. The size of the group public key and the length of the signature are independent on the numbers of the group.展开更多
The security of cloud data has always been a concern.Cloud server provider may maliciously tamper or delete user’s data for their own benefit,so data integrity audit is of great significance to verify whether data is...The security of cloud data has always been a concern.Cloud server provider may maliciously tamper or delete user’s data for their own benefit,so data integrity audit is of great significance to verify whether data is modified or not.Based on the general three-party audit architecture,a dynamic auditing scheme without bilinear pairings is proposed in this paper.It utilizes exponential operation instead of bilinear mapping to verify the validity of evidence.By establishing the mapping relation between logic index and tag index of data block with index transformation table,our scheme can easily support dynamic data operation.By hiding random numbers in the integrity evidence,our scheme can protect users’privacy information.Detailed security analysis shows that our scheme is secure against attacks such as forgery,replaying and substitution.Further experiments demonstrate that our scheme has lower computational overhead.展开更多
Ring signature and proxy signature are of vital importance to secure electronic commerce. Recently, the bilinear pairing such as Well pairing or Tate pairing on elliptic curves and hyperelliptic curves is playing an i...Ring signature and proxy signature are of vital importance to secure electronic commerce. Recently, the bilinear pairing such as Well pairing or Tate pairing on elliptic curves and hyperelliptic curves is playing an important role in security solutions. Several ID-based signature schemes have been put forward, many of which are based on bilinear pairings. In key management and moderate security demand scenarios, ID-based public key cryptosystem is more preferable than other public key infrastructure based systems. In this paper, an improved ID-based proxy ring signature scheme from bilinear pairings is proposed which combines the advantages of proxy signature and of ring signatures. Our scheme can guarantee the profits of the proxy signer via preventing the original signer form generating the proxy ring signature. Furthermore, bilinear pairings are introduced to minimize the computation overhead and to improve the related performance of our scheme. In contrast with Zhang＇s scheme, our scheme is a computational efficiency improvement for signature verification because the computational cost of bilinear pairings required is reduced from O（n） to O（ 1 ）. In addition, the proxy ring signature presented in this paper can perfectly satisfy all the security requirements of proxy ring signature, i. e. signer-ambiguity, non-forgeability, verification, non-deniability and distinguishability.展开更多
Key agreement protocols are essential for secure communications. In this paper, to solve the inherent key escrow problem of identity-based cryptography, an escrow-free certificate-based authenticated key agreement （C...Key agreement protocols are essential for secure communications. In this paper, to solve the inherent key escrow problem of identity-based cryptography, an escrow-free certificate-based authenticated key agreement （CB-AK） protocol with perfect forward secrecy is proposed. Our protocol makes use of pairings on elliptic curves. The protocol is described and its properties are discussed though comparison with Smart＇s protocol.展开更多
An authenticated group key agreement protocol suite (PAGKA) based on pairings is presented in this paper. This suite extends an efficient Diffie-Hellman-based protocol suite by introducing parings on elliptic curves a...An authenticated group key agreement protocol suite (PAGKA) based on pairings is presented in this paper. This suite extends an efficient Diffie-Hellman-based protocol suite by introducing parings on elliptic curves and public-key certificates. The result suite builds its security on the hardness of the bilinear Diffie-Hellman (BDH) problem in the random oracle model, and provides implicit key authentication, perfect forward secrecy and unknown key-share secrecy.展开更多
So far, most of the proposed group key exchange （GKE） protocols do not consider the attack when the adversary reveals the parties＇ ephemeral private keys without their long-term private keys, so these GKE protocols...So far, most of the proposed group key exchange （GKE） protocols do not consider the attack when the adversary reveals the parties＇ ephemeral private keys without their long-term private keys, so these GKE protocols are insecure on this attack. In this paper, for resisting above attack, we propose a dynamic authenticated group key exchange （AGKE） protocol in the ID-based setting. Different from previous ID-based protocols, our protocol does not utilize bilinear pairings, which makes it more efficient. At last, we analyze the security of the protocol in the cCK （enhanced Canetti-Krawczyk） security model.展开更多
Plate waste, defined as the quantity of edible food left uneaten after a meal, is a challenge for schools participating in the National School Lunch Program (NSLP). The new nutrition standards in the NSLP of United St...Plate waste, defined as the quantity of edible food left uneaten after a meal, is a challenge for schools participating in the National School Lunch Program (NSLP). The new nutrition standards in the NSLP of United States Department of Agriculture (USDA) were implemented at the beginning of school year (SY) 2012-2013. School foodservice authorities were concerned that the new standards would result in increased plate waste and reduced participation, especially by students who paid full prices for lunch. There are many reasons for plate waste, including students’ dislike of the foods served, the composition of meals, the environment in which students are eating, the lack of time to eat, or perhaps other factors. The objective of this study was to examine the relationship between entrée/vegetable “pairings” and plate waste by elementary school students pre- and post-implementation of the new school meal standards. Plate waste was measured to determine which entrée/vegetable pairs produced the least amount of waste. Plate waste of 144 and 305 entrée/vegetable pairings was analyzed, pre- and post-implementation, respectively. Our results indicated that more nutritious meals were offered during the post-implementation period. The new school meal standards led to no significant changes in entrée plate waste, but vegetable plate waste increased by 5.6%. As such, increases in the combined entrée/vegetable plate waste were evident from 40.4% pre-implementation to 43.5% post-implementation. The top five vegetables in terms of popularity were all starchy vegetables, the majority of which were potatoes in various processed forms. The least popular vegetables were dark-green leafy vegetables, such as steamed broccoli, both pre- and post-implementation. Chicken nuggets were the most popular entrée and were wasted the least. Understanding the dynamics of food pairings and providing desirable entrée and vegetable pairings can help reduce waste from school lunches.展开更多
Two digital multisignature schemes based on bilinear pairings were proposed. One of them is the sequential digital multisignature, and the other is the broadcasting digital multisignature. The scheme has the same secu...Two digital multisignature schemes based on bilinear pairings were proposed. One of them is the sequential digital multisignature, and the other is the broadcasting digital multisignature. The scheme has the same security as JI and LIs multisignature scheme, but the new scheme has the lower computation. So the new scheme is the multisignature which has high security and low computation. It has the theory meaning and extensive application under the condition of SmartCard, etc.展开更多
A proxy signature allows an entity,called original signer,to delegate its signing power to another entity,called proxy signer,to sign messages on its behalf.Proxy signatures have many practical applications and are ve...A proxy signature allows an entity,called original signer,to delegate its signing power to another entity,called proxy signer,to sign messages on its behalf.Proxy signatures have many practical applications and are very important cryptographic protocol.In this paper,we propose an efficient proxy signature scheme from bilinear pairings.We prove it secure in the random oracle model and analyze computation cost of our scheme.Our scheme satisfies all the properties required for proxy signatures.展开更多
We study theoretically the electrical shot noise properties of tunnel junctions between a normal metal and a superconductor with the mixture of singlet s-wave and chiral triplet p-wave pairing due to broken inversion ...We study theoretically the electrical shot noise properties of tunnel junctions between a normal metal and a superconductor with the mixture of singlet s-wave and chiral triplet p-wave pairing due to broken inversion symmetry. We investigate how the shot noise properties vary as the relative amplitude between the two parity components in the pairing potential is changed. It is demonstrated that some characteristics of the electrical shot noise properties of such tunnel junctions may depend sensitively on the relative amplitude between the two parity components in the pairing potential, and some significant changes may occur in the electrical shot noise properties when the relative amplitude between the two parity components is varied from the singlet s-wave pairing dominated regime to the chiral triplet p-wave pairing dominated regime. In the chiral triplet p-wave pairing dominated regime, the ratio of noise power to electric current is close to 2e both in the in-gap and in the out-gap region. In the singlet s-wave pairing dominated regime, the value of this ratio is close to 4e in the inner gap region but may reduce to about 2e in the outer gap region as the relative amplitude of the chiral triplet pairing component is increased. The variations of the differential shot noise with the bias voltage also exhibit some significantly different features in different regimes. Such different features can serve as useful diagnostic tools for the determination of the relative magnitude of the two parity components in the pairing potential.展开更多
Based on the GDH signature (short signature scheme) a probabilistic signature scheme is proposed in this paper with security proof.Then a new threshold proxy signature from bilinear pairings is proposed as well by us ...Based on the GDH signature (short signature scheme) a probabilistic signature scheme is proposed in this paper with security proof.Then a new threshold proxy signature from bilinear pairings is proposed as well by us ing the new probabilistic signature scheme and the properties of the Gap Diffie-Hellman (GDH)group (where the Computational Diffie-Hellman problem is hard but the Decisional Diffie-Hellman problem is easy to solve).Our constructions are based on the recently proposed GDH signature scheme of Bonel et al.s article.Bilinear pairings could be built from Weil pairing or Tate pairing.So most our constructions would be simpler,but still with high security.The proposed threshold proxy signature is the first one which is built from bilinear pairings.At the end of this paper security and performance of the threshold proxy signature scheme is also analyzed.展开更多
To solve the problem of security and efficiency of anonymous authentication in the vehicle Ad-hoc network(VANET), a conditional privacy protection authentication scheme for vehicular networks is proposed based on bili...To solve the problem of security and efficiency of anonymous authentication in the vehicle Ad-hoc network(VANET), a conditional privacy protection authentication scheme for vehicular networks is proposed based on bilinear pairings. In this scheme, the tamper-proof device in the roadside unit(RSU) is used to complete the message signature and authentication process together with the vehicle, which makes it more secure to communicate between RSU and trusted authority(TA) and faster to update system parameters and revoke the vehicle. And this is also cheaper than installing tamper-proof devices in each vehicle unit. Moreover, the scheme provide provable security proof under random oracle model(ROM), which shows that the proposed scheme can meet the security requirements such as conditional privacy, unforgeability, traceability, etc. And the results of simulation experiment demonstrate that this scheme not only of achieves high efficiency, but also has low message loss rate.展开更多
Aimed at enhancing privacy protection of location-based services（ LBS） in mobile Internet environment,an improved privacy scheme of high service quality on the basis of bilinear pairings theory and k-anonymity is pr...Aimed at enhancing privacy protection of location-based services（ LBS） in mobile Internet environment,an improved privacy scheme of high service quality on the basis of bilinear pairings theory and k-anonymity is proposed. In circular region of Euclidian distance,mobile terminal evenly generates some false locations,from which half optimal false locations are screened out according to position entropy,location and mapping background information. The anonymity obtains the effective guarantee,so as to realize privacy protection. Through security analyses,the scheme is proved not only to be able to realize such security features as privacy,anonymity and nonforgeability,but also able to resist query tracing attack. And the result of simulation shows that this scheme not only has better evenness in selecting false locations,but also improves efficiency in generating and selecting false nodes.展开更多
In this paper,we introduce the notion of G_(C)-X-injective modules,where X denotes a class of left S-modules and C represents a faithfully semidualizing bimodule.Under the condition that X satisfies certain hypotheses...In this paper,we introduce the notion of G_(C)-X-injective modules,where X denotes a class of left S-modules and C represents a faithfully semidualizing bimodule.Under the condition that X satisfies certain hypotheses,some properties and some equivalent characterizations of G_(C)-X-injective modules are investigated,and we also show that the triple(■,cores■,■)is a weak co-AB-context.As an application,two complete cotorsion pairs and a new model structure in Mod S are given.展开更多
To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.T...To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.This source is based on spontaneous four-wave mixing(SFWM)in a piece of shallow-ridge silicon waveguide.Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width,enabling broadband photon pair generation by SFWM across C band and O band.The spontaneous Raman scattering(SpRS)in silicon waveguides is also investigated experimentally.It shows that there are two regions in the spectrum of generated photons from SpRS,which could be used to achieve cross-band photon pair generation.A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated,through which cross-band photon pair generation is demonstrated experimentally.The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides.This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks.展开更多
Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford prod...Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford products with fixed sequences and compositions.Herein,we report the triethylborane/1,8-diazabicyclo[5.4.0]undec-7-ene(Et_3B/DBU)pair-mediated four-component switchable polymerization of propylene oxide(PO),CO_(2),phthalic anhydride(PA),and racemic lactide(rac-LA),which enables the on-demand synthesis of four different block copolymers,i.e.,poly(propylene phthalate)-b-polylactide(PPE-b-PLA),PPE-b-PLA-b-poly(propylene carbonate)(PPC),PPE-b-PPC-b-PLA,and PPE-b-PPCb-poly(propylene oxide)(PPO),through rationally modulating the Lewis pair(LP)ratio.Core to this protocol is that increasing the loading of Et_(3)B accelerates the ring-opening of PO while impeding the reactivity of rac-LA,thus allowing for fine-tuning of the thermodynamic and kinetic of the switchable polymerization.Therefore,the four polymerization cycles involving PO/PA ring-opening copolymerization(ROCOP),PO/CO_(2) ROCOP,rac-LA ring-opening polymerization(ROP),and PO ROP can be connected and discriminated in precisely programmed manners.展开更多
In this study,electrochemical C-H carboxylation of benzylamines with CO_(2) was reported.This linear paired electrolysis system enables efficient and economical synthesis of value-added α-amino acids(α-AAs) under mi...In this study,electrochemical C-H carboxylation of benzylamines with CO_(2) was reported.This linear paired electrolysis system enables efficient and economical synthesis of value-added α-amino acids(α-AAs) under mild conditions.Various substituted benzylamines containing diverse functional groups and even highly reactive moieties,such as cyano,amide and alkene groups could be successfully transformed to the carboxylated products.Notably,this method proved to be applicable to the late-stage modification of biorelevant compounds,highlighting its potential for synthetic chemistry.Mechanistic studies such as radical trapping experiments,kinetic isotope effect(KIE) tests and cyclic voltammetry(CV) studies provided useful insight into this transformation.展开更多
基金Supported bythe National Natural Science Foundationof China (60225007 ,60572155) the Science and Technology ResearchProject of Shanghai (04DZ07067)
文摘In the area of secure Web information system, mutual authentication and key agreement are essential between Web clients and servers. An efficient certificateless authenticated key agreement protocol for Web client/server setting is proposed, which uses pairings on certain elliptic curves. We show that the newly proposed key agreement protocol is practical and of great efficiency, meanwhile, it satisfies every desired security require ments for key agreement protocols.
基金Supported by the National Natural Science Foundation of China (60473029)
文摘Signcryption is a cryptographic primitive that performs signature and encryption simultaneously, at lower computational costs and communication overheads than the signature-then- encryption approach. In this paper, we propose an efficient multi-recipient signcryption scheme based on the bilinear pairings, which broadcasts a message to multiple users in a secure and authenticated manner. We prove its semantic security and unforgeability under the Gap Diffie-Hellman problem assumption in the random oracle model. The proposed scheme is more efficient than re-signcrypting a message n times using a signcryption scheme in terms of computational costs and communication overheads.
基金Supported by National Natural Science Foundation of China (No.60503006 and No.60403007) and Natural Science Foundation of Guangdong, China (No. 04205407).
文摘We argue that traditional identity-based systems from pairings seem unsuitable for designing group signature schemes due to the problem of key escrow. In this paper we first propose new ID-based public key systems without trusted PKG (Private Key Generator) from bilinear pairings. In our new ID-based systems, if the dishonest PKG impersonates an honest user to communicate with others, the user can provide a proof of treachery of the PKG afterwards, which is similar to certificate-based systems. Therefore, our systems reach the Girault’s trusted level 3. We then propose a group signature scheme under the new ID-based systems, the security and performance of which rely on the new systems. The size of the group public key and the length of the signature are independent on the numbers of the group.
基金This work is supported by the National Key R&D Program of China(2016YFB0800402)partially supported by the National Natural Science Foundation of China under Grant No.61232004and the Fundamental Research Funds for the Central Universities(2016YXMS020).
文摘The security of cloud data has always been a concern.Cloud server provider may maliciously tamper or delete user’s data for their own benefit,so data integrity audit is of great significance to verify whether data is modified or not.Based on the general three-party audit architecture,a dynamic auditing scheme without bilinear pairings is proposed in this paper.It utilizes exponential operation instead of bilinear mapping to verify the validity of evidence.By establishing the mapping relation between logic index and tag index of data block with index transformation table,our scheme can easily support dynamic data operation.By hiding random numbers in the integrity evidence,our scheme can protect users’privacy information.Detailed security analysis shows that our scheme is secure against attacks such as forgery,replaying and substitution.Further experiments demonstrate that our scheme has lower computational overhead.
基金Sponsored by the National Natural Science Foundation of China(Grant No.90104033).
文摘Ring signature and proxy signature are of vital importance to secure electronic commerce. Recently, the bilinear pairing such as Well pairing or Tate pairing on elliptic curves and hyperelliptic curves is playing an important role in security solutions. Several ID-based signature schemes have been put forward, many of which are based on bilinear pairings. In key management and moderate security demand scenarios, ID-based public key cryptosystem is more preferable than other public key infrastructure based systems. In this paper, an improved ID-based proxy ring signature scheme from bilinear pairings is proposed which combines the advantages of proxy signature and of ring signatures. Our scheme can guarantee the profits of the proxy signer via preventing the original signer form generating the proxy ring signature. Furthermore, bilinear pairings are introduced to minimize the computation overhead and to improve the related performance of our scheme. In contrast with Zhang＇s scheme, our scheme is a computational efficiency improvement for signature verification because the computational cost of bilinear pairings required is reduced from O（n） to O（ 1 ）. In addition, the proxy ring signature presented in this paper can perfectly satisfy all the security requirements of proxy ring signature, i. e. signer-ambiguity, non-forgeability, verification, non-deniability and distinguishability.
基金Supported by the National Natural Science Founda-tion of China (60225007, 60572155) and the Science and Technology Research Project of Shanghai (04DZ07067)
文摘Key agreement protocols are essential for secure communications. In this paper, to solve the inherent key escrow problem of identity-based cryptography, an escrow-free certificate-based authenticated key agreement （CB-AK） protocol with perfect forward secrecy is proposed. Our protocol makes use of pairings on elliptic curves. The protocol is described and its properties are discussed though comparison with Smart＇s protocol.
文摘An authenticated group key agreement protocol suite (PAGKA) based on pairings is presented in this paper. This suite extends an efficient Diffie-Hellman-based protocol suite by introducing parings on elliptic curves and public-key certificates. The result suite builds its security on the hardness of the bilinear Diffie-Hellman (BDH) problem in the random oracle model, and provides implicit key authentication, perfect forward secrecy and unknown key-share secrecy.
基金Supported by the National Natural Science Foundation ofChina (60773035)
文摘So far, most of the proposed group key exchange （GKE） protocols do not consider the attack when the adversary reveals the parties＇ ephemeral private keys without their long-term private keys, so these GKE protocols are insecure on this attack. In this paper, for resisting above attack, we propose a dynamic authenticated group key exchange （AGKE） protocol in the ID-based setting. Different from previous ID-based protocols, our protocol does not utilize bilinear pairings, which makes it more efficient. At last, we analyze the security of the protocol in the cCK （enhanced Canetti-Krawczyk） security model.
文摘Plate waste, defined as the quantity of edible food left uneaten after a meal, is a challenge for schools participating in the National School Lunch Program (NSLP). The new nutrition standards in the NSLP of United States Department of Agriculture (USDA) were implemented at the beginning of school year (SY) 2012-2013. School foodservice authorities were concerned that the new standards would result in increased plate waste and reduced participation, especially by students who paid full prices for lunch. There are many reasons for plate waste, including students’ dislike of the foods served, the composition of meals, the environment in which students are eating, the lack of time to eat, or perhaps other factors. The objective of this study was to examine the relationship between entrée/vegetable “pairings” and plate waste by elementary school students pre- and post-implementation of the new school meal standards. Plate waste was measured to determine which entrée/vegetable pairs produced the least amount of waste. Plate waste of 144 and 305 entrée/vegetable pairings was analyzed, pre- and post-implementation, respectively. Our results indicated that more nutritious meals were offered during the post-implementation period. The new school meal standards led to no significant changes in entrée plate waste, but vegetable plate waste increased by 5.6%. As such, increases in the combined entrée/vegetable plate waste were evident from 40.4% pre-implementation to 43.5% post-implementation. The top five vegetables in terms of popularity were all starchy vegetables, the majority of which were potatoes in various processed forms. The least popular vegetables were dark-green leafy vegetables, such as steamed broccoli, both pre- and post-implementation. Chicken nuggets were the most popular entrée and were wasted the least. Understanding the dynamics of food pairings and providing desirable entrée and vegetable pairings can help reduce waste from school lunches.
基金Natural Science Foundation of Fujian Province of China( Z0511024)
文摘Two digital multisignature schemes based on bilinear pairings were proposed. One of them is the sequential digital multisignature, and the other is the broadcasting digital multisignature. The scheme has the same security as JI and LIs multisignature scheme, but the new scheme has the lower computation. So the new scheme is the multisignature which has high security and low computation. It has the theory meaning and extensive application under the condition of SmartCard, etc.
基金Supported by the National Natural Science Foundation of China(No.60842002,60673070)The National High-tech Research and Development Plan of China(No.2007AA01-Z409)+2 种基金The Fundamental Research Funds for the Central Universities Grant No.B1020211China Postdoctoral Science Foundation Funded ProjectThe"Six Talent Peaks Program"of Jiangsu Province of China and Pro-gram for New Century Excellent Talents in Hohai Uni-versity
文摘A proxy signature allows an entity,called original signer,to delegate its signing power to another entity,called proxy signer,to sign messages on its behalf.Proxy signatures have many practical applications and are very important cryptographic protocol.In this paper,we propose an efficient proxy signature scheme from bilinear pairings.We prove it secure in the random oracle model and analyze computation cost of our scheme.Our scheme satisfies all the properties required for proxy signatures.
文摘We study theoretically the electrical shot noise properties of tunnel junctions between a normal metal and a superconductor with the mixture of singlet s-wave and chiral triplet p-wave pairing due to broken inversion symmetry. We investigate how the shot noise properties vary as the relative amplitude between the two parity components in the pairing potential is changed. It is demonstrated that some characteristics of the electrical shot noise properties of such tunnel junctions may depend sensitively on the relative amplitude between the two parity components in the pairing potential, and some significant changes may occur in the electrical shot noise properties when the relative amplitude between the two parity components is varied from the singlet s-wave pairing dominated regime to the chiral triplet p-wave pairing dominated regime. In the chiral triplet p-wave pairing dominated regime, the ratio of noise power to electric current is close to 2e both in the in-gap and in the out-gap region. In the singlet s-wave pairing dominated regime, the value of this ratio is close to 4e in the inner gap region but may reduce to about 2e in the outer gap region as the relative amplitude of the chiral triplet pairing component is increased. The variations of the differential shot noise with the bias voltage also exhibit some significantly different features in different regimes. Such different features can serve as useful diagnostic tools for the determination of the relative magnitude of the two parity components in the pairing potential.
文摘Based on the GDH signature (short signature scheme) a probabilistic signature scheme is proposed in this paper with security proof.Then a new threshold proxy signature from bilinear pairings is proposed as well by us ing the new probabilistic signature scheme and the properties of the Gap Diffie-Hellman (GDH)group (where the Computational Diffie-Hellman problem is hard but the Decisional Diffie-Hellman problem is easy to solve).Our constructions are based on the recently proposed GDH signature scheme of Bonel et al.s article.Bilinear pairings could be built from Weil pairing or Tate pairing.So most our constructions would be simpler,but still with high security.The proposed threshold proxy signature is the first one which is built from bilinear pairings.At the end of this paper security and performance of the threshold proxy signature scheme is also analyzed.
文摘To solve the problem of security and efficiency of anonymous authentication in the vehicle Ad-hoc network(VANET), a conditional privacy protection authentication scheme for vehicular networks is proposed based on bilinear pairings. In this scheme, the tamper-proof device in the roadside unit(RSU) is used to complete the message signature and authentication process together with the vehicle, which makes it more secure to communicate between RSU and trusted authority(TA) and faster to update system parameters and revoke the vehicle. And this is also cheaper than installing tamper-proof devices in each vehicle unit. Moreover, the scheme provide provable security proof under random oracle model(ROM), which shows that the proposed scheme can meet the security requirements such as conditional privacy, unforgeability, traceability, etc. And the results of simulation experiment demonstrate that this scheme not only of achieves high efficiency, but also has low message loss rate.
基金supported by the National Natural Science Foundation of China(61772159,61300124,61300216)the Science and Technology Research Program of Henan Province(172102310677)
文摘Aimed at enhancing privacy protection of location-based services（ LBS） in mobile Internet environment,an improved privacy scheme of high service quality on the basis of bilinear pairings theory and k-anonymity is proposed. In circular region of Euclidian distance,mobile terminal evenly generates some false locations,from which half optimal false locations are screened out according to position entropy,location and mapping background information. The anonymity obtains the effective guarantee,so as to realize privacy protection. Through security analyses,the scheme is proved not only to be able to realize such security features as privacy,anonymity and nonforgeability,but also able to resist query tracing attack. And the result of simulation shows that this scheme not only has better evenness in selecting false locations,but also improves efficiency in generating and selecting false nodes.
文摘In this paper,we introduce the notion of G_(C)-X-injective modules,where X denotes a class of left S-modules and C represents a faithfully semidualizing bimodule.Under the condition that X satisfies certain hypotheses,some properties and some equivalent characterizations of G_(C)-X-injective modules are investigated,and we also show that the triple(■,cores■,■)is a weak co-AB-context.As an application,two complete cotorsion pairs and a new model structure in Mod S are given.
基金supported by the Quantum Science and Technology-National Science and Technology Major Project (Grant No.2024ZD0302502 for WZ)the National Natural Science Foundation of China(Grant No.92365210 for WZ)+1 种基金Tsinghua Initiative Scientific Research Program (for WZ)the project of Tsinghua University-Zhuhai Huafa Industrial Share Company Joint Institute for Architecture Optoelectronic Technologies (JIAOT,for YH)。
文摘To fully utilize the resources provided by optical fiber networks,a cross-band quantum light source generating photon pairs,where one photon in a pair is at C band and the other is at O band,is proposed in this work.This source is based on spontaneous four-wave mixing(SFWM)in a piece of shallow-ridge silicon waveguide.Theoretical analysis shows that the waveguide dispersion could be tailored by adjusting the ridge width,enabling broadband photon pair generation by SFWM across C band and O band.The spontaneous Raman scattering(SpRS)in silicon waveguides is also investigated experimentally.It shows that there are two regions in the spectrum of generated photons from SpRS,which could be used to achieve cross-band photon pair generation.A chip of shallow-ridge silicon waveguide samples with different ridge widths has been fabricated,through which cross-band photon pair generation is demonstrated experimentally.The experimental results show that the source can be achieved using dispersion-optimized shallow-ridge silicon waveguides.This cross-band quantum light source provides a way to develop new fiber-based quantum communication functions utilizing both C band and O band and extends applications of quantum networks.
基金financially supported by National Key R&D Program Young Scientists Project(No.2023YFC3903100)the National Natural Science Foundation of China(No.22322503)analytical and testing assistance from the Analysis and Testing Center of HUST。
文摘Switchable polymerization is emerging as a powerful tool to construct block copolymers directly from mixtures of monomers.However,current achievements typically iterate between two polymerization cycles to afford products with fixed sequences and compositions.Herein,we report the triethylborane/1,8-diazabicyclo[5.4.0]undec-7-ene(Et_3B/DBU)pair-mediated four-component switchable polymerization of propylene oxide(PO),CO_(2),phthalic anhydride(PA),and racemic lactide(rac-LA),which enables the on-demand synthesis of four different block copolymers,i.e.,poly(propylene phthalate)-b-polylactide(PPE-b-PLA),PPE-b-PLA-b-poly(propylene carbonate)(PPC),PPE-b-PPC-b-PLA,and PPE-b-PPCb-poly(propylene oxide)(PPO),through rationally modulating the Lewis pair(LP)ratio.Core to this protocol is that increasing the loading of Et_(3)B accelerates the ring-opening of PO while impeding the reactivity of rac-LA,thus allowing for fine-tuning of the thermodynamic and kinetic of the switchable polymerization.Therefore,the four polymerization cycles involving PO/PA ring-opening copolymerization(ROCOP),PO/CO_(2) ROCOP,rac-LA ring-opening polymerization(ROP),and PO ROP can be connected and discriminated in precisely programmed manners.
基金Financial support from National Key R&D Program of China (No.2023YFA1507203)National Natural Science Foundation of China (Nos.22371149 and 22188101)+3 种基金the Fundamental Research Funds for the Central Universities (No.63224098)Frontiers Science Center for New Organic Matter,Nankai University (No.63181206)Nankai University are gratefully acknowledgedthe Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘In this study,electrochemical C-H carboxylation of benzylamines with CO_(2) was reported.This linear paired electrolysis system enables efficient and economical synthesis of value-added α-amino acids(α-AAs) under mild conditions.Various substituted benzylamines containing diverse functional groups and even highly reactive moieties,such as cyano,amide and alkene groups could be successfully transformed to the carboxylated products.Notably,this method proved to be applicable to the late-stage modification of biorelevant compounds,highlighting its potential for synthetic chemistry.Mechanistic studies such as radical trapping experiments,kinetic isotope effect(KIE) tests and cyclic voltammetry(CV) studies provided useful insight into this transformation.
