In order to meet people’s demand for various types of network services,researchers have conducted extensive research on authentication schemes for multi-server architecture.Although various schemes have been proposed...In order to meet people’s demand for various types of network services,researchers have conducted extensive research on authentication schemes for multi-server architecture.Although various schemes have been proposed,most of them still have safety defects and fail to meet safety requirements.Recently,Haq et al presented an efficient Hash-based authenticated key agreement scheme for multi-server scheme and claimed that their scheme can withstand all well-known attacks.However,we find that their scheme is vulnerable to replay attack,tracking attack and malicious server impersonation user attack.Then we propose an improved scheme.We also analyze the security of the improved scheme and compare with Haq et al’s scheme in security and computational efficiency.Furthermore,we use the AVISPA(Automated Validation of Internet Security Protocols and Applications)tool to verify the security of the improved scheme.展开更多
During the past decade,rapid advances in wireless communication technologies have made it possible for users to access desired services using hand-held devices.Service providers have hosted multiple servers to ensure ...During the past decade,rapid advances in wireless communication technologies have made it possible for users to access desired services using hand-held devices.Service providers have hosted multiple servers to ensure seamless online services to end-users.To ensure the security of this online communication,researchers have proposed several multi-server authentication schemes incorporating various cryptographic primitives.Due to the low power and computational capacities of mobile devices,the hash-based multi-server authenticated key agreement schemes with offline Registration Server(RS)are the most efficient choice.Recently,Kumar-Om presented such a scheme and proved its security against all renowned attacks.However,we find that their scheme bears an incorrect login phase,and is unsafe to the trace attack,the Session-Specific Temporary Information Attack(SSTIA),and the Key Compromise Impersonation Attack(KCIA).In fact,all of the existing multi-server authentication schemes(hash-based with offline RS)do not withstand KCLA.To deal with this situation,we propose an improved hash-based multi-server authentication scheme(with offline RS).We analyze the security of the proposed scheme under the random oracle model and use the t4Automated Validation of Internet Security Protocols and Applications''(AVISPA)tool.The comparative analysis of communication overhead and computational complexity metrics shows the efficiency of the proposed scheme.展开更多
Multi-server authenticated key agreement schemes have attracted great attention to both academia and industry in recent years.However,traditional authenticated key agreement schemes in the single-server environment ar...Multi-server authenticated key agreement schemes have attracted great attention to both academia and industry in recent years.However,traditional authenticated key agreement schemes in the single-server environment are not suitable for the multi-server environment because the user has to register on each server when he/she wishes to log in various servers for different service.Moreover,it is unreasonable to consider all servers are trusted since the server in a multi-server environment may be a semi-trusted party.In order to overcome these difficulties,we designed a secure three-factor multi-server authenticated key agreement protocol based on elliptic curve cryptography,which needs the user to register only once at the registration center in order to access all semi-trusted servers.The proposed scheme can not only against various known attacks but also provides high computational efficiency.Besides,we have proved our scheme fulfills mutual authentication by using the authentication test method.展开更多
Since network services are provided cooperatively by multiple servers in the lnternet, the authentication protocols for multiserver architecture are required by Internetbased services, such as online game, online trad...Since network services are provided cooperatively by multiple servers in the lnternet, the authentication protocols for multiserver architecture are required by Internetbased services, such as online game, online trade and so on. Recently, Li et al. analyzed Lee et al.＇s protocol and proposed an improved dynamic identity based authentication protocol for multi-server architecture. They claimed that their protocol provides user＇s anonymity, mutual authentication and the session key agreement against several kinds of attacks. In this paper, a cryptanalysis on Lee et al.＇s scheme shows that Lee et al＇s protocol is also vulnerable to malicious server attack, stolen smart card attack and leak-of-verifier attack. Moreover, Li e/ al.＇s improved protocol is also vulnerable to all these attacks. Further cryptanalysis reveals that Li et al.＇s improved protocol is susceptible to collusion attack.展开更多
With the development of communication technologies,various mobile devices and different types of mobile services became available.The emergence of these services has brought great convenience to our lives.The multi-se...With the development of communication technologies,various mobile devices and different types of mobile services became available.The emergence of these services has brought great convenience to our lives.The multi-server architecture authentication protocols for mobile cloud computing were proposed to ensure the security and availability between mobile devices and mobile services.However,most of the protocols did not consider the case of hierarchical authentication.In the existing protocol,when a mobile user once registered at the registration center,he/she can successfully authenticate with all mobile service providers that are registered at the registration center,but real application scenarios are not like this.For some specific scenarios,some mobile service providers want to provide service only for particular users.For this reason,we propose a new hierarchical multi-server authentication protocol for mobile cloud computing.The proposed protocol ensures only particular types of users can successfully authenticate with certain types of mobile service providers.The proposed protocol reduces computing and communication costs by up to 42.6%and 54.2%compared to two superior protocols.The proposed protocol can also resist the attacks known so far.展开更多
Currently, smart card based remote user authentication schemes have been widely adopted due to their low cost and convenient portability. With the purpose of using various different internet services with single regis...Currently, smart card based remote user authentication schemes have been widely adopted due to their low cost and convenient portability. With the purpose of using various different internet services with single registration and to protect the users from being tracked, various dynamic ID based multi-server authentication protocols have been proposed. Recently, Li et al. proposed an efficient and secure dynamic ID based authentication protocol using smart cards. They claimed that their protocol provides strong security. In this paper, we have demonstrated that Li et al.’s protocol is vulnerable to replay attack, denial of service attack, smart card lost attack, eavesdropping attack and server spoofing attacks.展开更多
针对脑电数据不足和数据异构导致运动想象解码性能下降,提出一种融合双服务器结构和多头注意力机制的联邦学习模型,实现异构脑电数据的运动想象多任务识别。通过欧几里得对齐,减少客户端数据分布差异。设计双服务器架构解决数据异构,服...针对脑电数据不足和数据异构导致运动想象解码性能下降,提出一种融合双服务器结构和多头注意力机制的联邦学习模型,实现异构脑电数据的运动想象多任务识别。通过欧几里得对齐,减少客户端数据分布差异。设计双服务器架构解决数据异构,服务器一选择并共享本地模型的最佳特征,将其作为全局共享资源改进客户端更新策略,解决客户端漂移问题;服务器二聚合本地模型参数,并进行全局参数微调训练,增强模型适应不同场景脑电数据异构的能力,提高全局模型的通用性。利用Transfomer多头自注意力,提高运动想象脑电的特征表示和模型学习能力。在BCI IV 2a脑机接口竞赛数据集上,该模型与联邦学习基准模型相比,脑电解码平均准确率提升了21.05百分点,Kappa值提升了0.283。在两个脑电数据集进行不同用户、不同环境和设备的跨数据集测试,脑电解码分别获得了71.13%和86.63%的平均准确率以及0.615和0.822的Kappa系数。结果表明:该模型在多用户、多设备且数据高度异构的场景下,运动想象脑电识别能够获得较好的性能,具有较强的泛化性。展开更多
当今科技飞速发展,隐私保护成为一个重要议题.为了确保数据的安全性,通常选择将数据加密后存储在云服务器上,然而这样云服务器无法对加密后的数据进行计算、统计等有效处理,从而使得很多应用场景受限.为了解决这个问题,提出一种基于环...当今科技飞速发展,隐私保护成为一个重要议题.为了确保数据的安全性,通常选择将数据加密后存储在云服务器上,然而这样云服务器无法对加密后的数据进行计算、统计等有效处理,从而使得很多应用场景受限.为了解决这个问题,提出一种基于环上容错学习(ring learning with error,R-LWE)问题的PKE-MET(public-key encryption with a multiple-ciphertext equality test)方案,并给出了正确性和安全性分析.该方案允许云服务器同时对多个密文执行相等性测试,还能够抵抗量子计算攻击.基于Palisade库对方案进行了实现,从理论与实现的角度与其他方案进行了比较分析.相较于其他方案,该方案具有高效、运行时间短的优点.展开更多
基金Supported by the Applied Basic and Advanced Technology Research Programs of Tianjin(15JCYBJC15900)。
文摘In order to meet people’s demand for various types of network services,researchers have conducted extensive research on authentication schemes for multi-server architecture.Although various schemes have been proposed,most of them still have safety defects and fail to meet safety requirements.Recently,Haq et al presented an efficient Hash-based authenticated key agreement scheme for multi-server scheme and claimed that their scheme can withstand all well-known attacks.However,we find that their scheme is vulnerable to replay attack,tracking attack and malicious server impersonation user attack.Then we propose an improved scheme.We also analyze the security of the improved scheme and compare with Haq et al’s scheme in security and computational efficiency.Furthermore,we use the AVISPA(Automated Validation of Internet Security Protocols and Applications)tool to verify the security of the improved scheme.
文摘During the past decade,rapid advances in wireless communication technologies have made it possible for users to access desired services using hand-held devices.Service providers have hosted multiple servers to ensure seamless online services to end-users.To ensure the security of this online communication,researchers have proposed several multi-server authentication schemes incorporating various cryptographic primitives.Due to the low power and computational capacities of mobile devices,the hash-based multi-server authenticated key agreement schemes with offline Registration Server(RS)are the most efficient choice.Recently,Kumar-Om presented such a scheme and proved its security against all renowned attacks.However,we find that their scheme bears an incorrect login phase,and is unsafe to the trace attack,the Session-Specific Temporary Information Attack(SSTIA),and the Key Compromise Impersonation Attack(KCIA).In fact,all of the existing multi-server authentication schemes(hash-based with offline RS)do not withstand KCLA.To deal with this situation,we propose an improved hash-based multi-server authentication scheme(with offline RS).We analyze the security of the proposed scheme under the random oracle model and use the t4Automated Validation of Internet Security Protocols and Applications''(AVISPA)tool.The comparative analysis of communication overhead and computational complexity metrics shows the efficiency of the proposed scheme.
基金This work is supported by the Sichuan education department research project(No.16226483)Sichuan Science and Technology Program(No.2018GZDZX0008)+1 种基金Chengdu Science and Technology Program(No.2018-YF08-00007-GX)the National Natural Science Foundation of China(No.61872087).
文摘Multi-server authenticated key agreement schemes have attracted great attention to both academia and industry in recent years.However,traditional authenticated key agreement schemes in the single-server environment are not suitable for the multi-server environment because the user has to register on each server when he/she wishes to log in various servers for different service.Moreover,it is unreasonable to consider all servers are trusted since the server in a multi-server environment may be a semi-trusted party.In order to overcome these difficulties,we designed a secure three-factor multi-server authenticated key agreement protocol based on elliptic curve cryptography,which needs the user to register only once at the registration center in order to access all semi-trusted servers.The proposed scheme can not only against various known attacks but also provides high computational efficiency.Besides,we have proved our scheme fulfills mutual authentication by using the authentication test method.
基金supported by the Key Program of NSFC-Guangdong Union Foundation under Grant No.U1135002Young Foundation of Humanities and Social Sciences of MOE (Ministry of Education in China) of under Grant No.11YJCZH160Foundation for Young Scientists of Jiangxi Province of China under Grant No.20133BCB23016
文摘Since network services are provided cooperatively by multiple servers in the lnternet, the authentication protocols for multiserver architecture are required by Internetbased services, such as online game, online trade and so on. Recently, Li et al. analyzed Lee et al.＇s protocol and proposed an improved dynamic identity based authentication protocol for multi-server architecture. They claimed that their protocol provides user＇s anonymity, mutual authentication and the session key agreement against several kinds of attacks. In this paper, a cryptanalysis on Lee et al.＇s scheme shows that Lee et al＇s protocol is also vulnerable to malicious server attack, stolen smart card attack and leak-of-verifier attack. Moreover, Li e/ al.＇s improved protocol is also vulnerable to all these attacks. Further cryptanalysis reveals that Li et al.＇s improved protocol is susceptible to collusion attack.
基金This work is funded by the Chengdu Science and Technology Bureau No.2016-XT00-00015-GXthe Civil Aviation Administration of China No.PSDSA201802.
文摘With the development of communication technologies,various mobile devices and different types of mobile services became available.The emergence of these services has brought great convenience to our lives.The multi-server architecture authentication protocols for mobile cloud computing were proposed to ensure the security and availability between mobile devices and mobile services.However,most of the protocols did not consider the case of hierarchical authentication.In the existing protocol,when a mobile user once registered at the registration center,he/she can successfully authenticate with all mobile service providers that are registered at the registration center,but real application scenarios are not like this.For some specific scenarios,some mobile service providers want to provide service only for particular users.For this reason,we propose a new hierarchical multi-server authentication protocol for mobile cloud computing.The proposed protocol ensures only particular types of users can successfully authenticate with certain types of mobile service providers.The proposed protocol reduces computing and communication costs by up to 42.6%and 54.2%compared to two superior protocols.The proposed protocol can also resist the attacks known so far.
文摘Currently, smart card based remote user authentication schemes have been widely adopted due to their low cost and convenient portability. With the purpose of using various different internet services with single registration and to protect the users from being tracked, various dynamic ID based multi-server authentication protocols have been proposed. Recently, Li et al. proposed an efficient and secure dynamic ID based authentication protocol using smart cards. They claimed that their protocol provides strong security. In this paper, we have demonstrated that Li et al.’s protocol is vulnerable to replay attack, denial of service attack, smart card lost attack, eavesdropping attack and server spoofing attacks.
文摘针对脑电数据不足和数据异构导致运动想象解码性能下降,提出一种融合双服务器结构和多头注意力机制的联邦学习模型,实现异构脑电数据的运动想象多任务识别。通过欧几里得对齐,减少客户端数据分布差异。设计双服务器架构解决数据异构,服务器一选择并共享本地模型的最佳特征,将其作为全局共享资源改进客户端更新策略,解决客户端漂移问题;服务器二聚合本地模型参数,并进行全局参数微调训练,增强模型适应不同场景脑电数据异构的能力,提高全局模型的通用性。利用Transfomer多头自注意力,提高运动想象脑电的特征表示和模型学习能力。在BCI IV 2a脑机接口竞赛数据集上,该模型与联邦学习基准模型相比,脑电解码平均准确率提升了21.05百分点,Kappa值提升了0.283。在两个脑电数据集进行不同用户、不同环境和设备的跨数据集测试,脑电解码分别获得了71.13%和86.63%的平均准确率以及0.615和0.822的Kappa系数。结果表明:该模型在多用户、多设备且数据高度异构的场景下,运动想象脑电识别能够获得较好的性能,具有较强的泛化性。
文摘随着移动边缘计算(mobile edge computing,MEC)技术的不断演进发展,大量的用户设备分散在边缘服务器密集部署的各个区域内。然而,在任务时延与资源受限的前提下,如何选择合适的服务器进行任务卸载,仍然是一个具有挑战性的难题。研究用户-服务器关联、卸载比例以及资源分配的联合优化问题,在考虑需求和服务异构性下最小化系统能耗。该问题被建模为混合整数非线性规划问题,并分解为用户-服务器关联子问题、卸载率和资源分配子问题进行求解。对于第一个子问题,在同时考虑通信质量与服务类型条件下,利用改良的带权匈牙利算法(Kuhn-Munkres matching algorithm,K-M)实现用户-服务器关联。为了处理第二个高度非凸问题,提出一种有效的双层算法,内层采用拉格朗日对偶法得到计算与通信资源分配;外层采用一维搜索方法得到卸载比例。最后,利用块坐标下降技术交替求解两个子问题,直到收敛。仿真结果表明,与随机算法、贪婪算法和带权匈牙利匹配-本地计算(Kuhn-Munkres matching and local computing,KM-LC)算法相比,文中所提出的算法能有效降低系统能耗。
文摘当今科技飞速发展,隐私保护成为一个重要议题.为了确保数据的安全性,通常选择将数据加密后存储在云服务器上,然而这样云服务器无法对加密后的数据进行计算、统计等有效处理,从而使得很多应用场景受限.为了解决这个问题,提出一种基于环上容错学习(ring learning with error,R-LWE)问题的PKE-MET(public-key encryption with a multiple-ciphertext equality test)方案,并给出了正确性和安全性分析.该方案允许云服务器同时对多个密文执行相等性测试,还能够抵抗量子计算攻击.基于Palisade库对方案进行了实现,从理论与实现的角度与其他方案进行了比较分析.相较于其他方案,该方案具有高效、运行时间短的优点.
