近年来无线通信技术的发展极大促进了移动设备的普及,用户可以使用移动设备随时随地访问到网络服务.由于网络空间的虚拟性,数字签名作为一种具有消息完整性认证、可鉴别性和不可否认性的技术应运而生.但是,移动设备自身存在易丢失或被...近年来无线通信技术的发展极大促进了移动设备的普及,用户可以使用移动设备随时随地访问到网络服务.由于网络空间的虚拟性,数字签名作为一种具有消息完整性认证、可鉴别性和不可否认性的技术应运而生.但是,移动设备自身存在易丢失或被劫持等安全隐患,导致对签名密钥(数字签名的信任根)的保护相对较弱.为了保护密钥安全,国内外学者提出了两方协同签名,防止密钥存储或使用过程中存在欺诈或盗用等恶意行为.针对GM T 0003—2012《SM2椭圆曲线公钥密码术》标准中的SM2数字签名算法,考虑客户端服务器这种非平衡构架,设计一种轻量级的SM2两方协同签名协议是具有理论和应用价值的.具体来讲,客户端和服务器以交互的方式产生有效签名,同时保证此过程中没有恢复完整的签名密钥.所提协议的性能也可通过实验测试的结果得到佐证,即客户端生成单个签名操作需4.381 ms,大致相当于遵循原始SM2签名算法所需的耗时,可见SM2两方协同签名具有很强的实用性.展开更多
‘Co-control',or synergistically reducing CO_(2)and local air polluta nt emissions,is an important strategy for cities to achieve'low carb on'and'blue sky'simultaneously.However,there were few stud...‘Co-control',or synergistically reducing CO_(2)and local air polluta nt emissions,is an important strategy for cities to achieve'low carb on'and'blue sky'simultaneously.However,there were few studies to evaluate and compare the level of co-control of CO_(2) and local air pollutants in cities year.The present study proposed qualitative and quantitative methods to evaluate the level of co-control of CO_(2)and three local air pollutant(SO_(2).NOX,and particulate matter PM)emissions in key environmental protection cities in China over two periods(2012-2015 and 2015-2018).Statistical analysis found that,though three local air pollutant emissions positively correlated with CO_(2) emission,no significantly positive correlation was found between local air pollutants emission reductions and CO_(2) emission reductions,indicating that co-control effects were poor in general.By using the co-control effect coordinate system,qualitative evaluation showed that less than half of the sample cities could achieve co-control of the total amount of CO_(2) and local air pollutants.By employing the indicator of emission reduction equivalence(EReq),quantitative evaluation showed that the co-control level of the sample cities improved in 2015-2018 compared with 2012-2015.Further regression analysis showed that,reducing coal consumption and economic development significantly enhanced the co-control performance of the observed cities.The present case study proved that the proposed methods for evaluation and comparison of the city co-control performance works well,and can be used in other countries and regions to promote global cities racing to carbon and local air pollutants co-control.展开更多
文摘近年来无线通信技术的发展极大促进了移动设备的普及,用户可以使用移动设备随时随地访问到网络服务.由于网络空间的虚拟性,数字签名作为一种具有消息完整性认证、可鉴别性和不可否认性的技术应运而生.但是,移动设备自身存在易丢失或被劫持等安全隐患,导致对签名密钥(数字签名的信任根)的保护相对较弱.为了保护密钥安全,国内外学者提出了两方协同签名,防止密钥存储或使用过程中存在欺诈或盗用等恶意行为.针对GM T 0003—2012《SM2椭圆曲线公钥密码术》标准中的SM2数字签名算法,考虑客户端服务器这种非平衡构架,设计一种轻量级的SM2两方协同签名协议是具有理论和应用价值的.具体来讲,客户端和服务器以交互的方式产生有效签名,同时保证此过程中没有恢复完整的签名密钥.所提协议的性能也可通过实验测试的结果得到佐证,即客户端生成单个签名操作需4.381 ms,大致相当于遵循原始SM2签名算法所需的耗时,可见SM2两方协同签名具有很强的实用性.
基金This work was co-supported by The Energy Foundation project‘Co-control effect assessment of deep decarbonization measures and the co-control path way in China'(G-1809-28536)the Major Projects of the National Social Science Foundation‘Study on action plan for peaking carbon emissions by 2030 in China'(21ZDA085).
文摘‘Co-control',or synergistically reducing CO_(2)and local air polluta nt emissions,is an important strategy for cities to achieve'low carb on'and'blue sky'simultaneously.However,there were few studies to evaluate and compare the level of co-control of CO_(2) and local air pollutants in cities year.The present study proposed qualitative and quantitative methods to evaluate the level of co-control of CO_(2)and three local air pollutant(SO_(2).NOX,and particulate matter PM)emissions in key environmental protection cities in China over two periods(2012-2015 and 2015-2018).Statistical analysis found that,though three local air pollutant emissions positively correlated with CO_(2) emission,no significantly positive correlation was found between local air pollutants emission reductions and CO_(2) emission reductions,indicating that co-control effects were poor in general.By using the co-control effect coordinate system,qualitative evaluation showed that less than half of the sample cities could achieve co-control of the total amount of CO_(2) and local air pollutants.By employing the indicator of emission reduction equivalence(EReq),quantitative evaluation showed that the co-control level of the sample cities improved in 2015-2018 compared with 2012-2015.Further regression analysis showed that,reducing coal consumption and economic development significantly enhanced the co-control performance of the observed cities.The present case study proved that the proposed methods for evaluation and comparison of the city co-control performance works well,and can be used in other countries and regions to promote global cities racing to carbon and local air pollutants co-control.
