The environmental magnetic proxies of stalagmites hold significant potential for reconstructing regional hydroclimate changes by revealing the content and grain size of magnetic particles within stalagmites.In this st...The environmental magnetic proxies of stalagmites hold significant potential for reconstructing regional hydroclimate changes by revealing the content and grain size of magnetic particles within stalagmites.In this study,we present the contents and grain sizes of magnetic particles within a stalagmite SZ-1,from Shizhu Cave in southwestern China from 70.4 to 22.3 thousand years ago(ka)during the last glacial period.Specifically,the parameters IRM_(soft),soil-derived magnetic minerals,and ARM/SIRM(anhysteretic remanent magnetization/saturation isothermal remanent magnetization),the ratio of fine magnetic particles to total ferrimagnetic particles preserved in stalagmite SZ-1,indicate the fluctuation of regional precipitation.Obvious half-precessional cycles are evident in these two proxies,indicating that hydroclimatic variations in southwestern China may predominantly arise from the heat and moisture transported from tropical oceans.These variations are likely influenced by shifts in the Intertropical Convergence Zone and fluctuations in the Asian Summer Monsoon.展开更多
: Comprehensive studies on a stalagmite from the Panlong cave, Guilin, have shown that the isotopic records and sedimentary characteristics can reflect the changes of both palaeotemperatures and palaeorainfall, that i...: Comprehensive studies on a stalagmite from the Panlong cave, Guilin, have shown that the isotopic records and sedimentary characteristics can reflect the changes of both palaeotemperatures and palaeorainfall, that is to say, it is possible to get some information about the changes in climate of the area from the speleothem. The results suggest that: (1) the Younger Dryas event might have persisted in the area from 11 300 to 10 800 a B.P.; (2) from 9000 to 7000 a B.P., the climate got warmer and wetter, and the summer monsoon was gradually enhanced; (3) from 7000 to 4500 a B.P., the climate was warm and wet, and the summer monsoon prevailed; and (4) from 4500 a B.P. on, the summer monsoon was weakened and the modern climate pattern appeared, but there were several cold and dry periods, namely, from 4000 to 2500 a B.P., ca. 2400 a B.P. and < 1000 a B.P.展开更多
In this paper the authors report a preliminary study on a Holocene stalagmite from Shihua Cave in Southwest Beijing.The result shows that the thickness of annual growth layers which is defined by annual deposit hiatus...In this paper the authors report a preliminary study on a Holocene stalagmite from Shihua Cave in Southwest Beijing.The result shows that the thickness of annual growth layers which is defined by annual deposit hiatuses preserve changes with precipitation. In light with the thickness of annual layers the authors reconstruct the climatic variation history of the last 2300 years in Beijing area.The climatic patterns seems to reappear irregularly on millennium to decade scales in the last 1000 years. The stable isotopic sequence interprets that the climate and environment in Beijing could be separated into two stages in the late Holocene: the monsoon was strong and the environment was wet in the former stage and in the latter stage the monsoon was weak and the environment was dry. The annual layers and oxygen isotope could be taken as natural signals and carbon isotope as a comprehensive signal containing the natural information and the information of anthropogenic activity.展开更多
The stalagmite δ18O record is known to be associated with the climate, but the specifics of the relationship remain unclear. It may not represent variation in air temperature or precipitation, but instead reflect int...The stalagmite δ18O record is known to be associated with the climate, but the specifics of the relationship remain unclear. It may not represent variation in air temperature or precipitation, but instead reflect integral changes of monsoon circulation, especially water vapor sources(the so-called "circulation effect"). Since large-scale atmospheric-oceanic modes such as the Atlantic Multidecadal Oscillation(AMO), Pacific Decadal Oscillation(PDO), and North Atlantic Oscillation(NAO) exert significant effects on Asian monsoon, in this paper the authors investigate the relationships of the East Asian stalagmite δ18O record with these modes. The last three centuries form the focus of our study, for which the authors use reconstructed as well as instrumental data. Considering the impacts of human activity, our analysis is conducted with respect to two periods—the pre- and post-industrial periods. The results show significant lead-lag connections: a positive correlation peaks when the PDO leads East Asian stalagmite δ18O by 3 years, which is persistent over the past 300 years; while the relationships of the AMO and NAO with the East Asian stalagmite δ18O record show significant differences in the post-industrial relative to the pre-industrial period. This implies that the East Asian stalagmite δ18O record may primarily reflect the PDO signal.展开更多
Spelean stalagmite dating using thermal ionization mass spectrometry (TIMS) on the basis of U Th disequilibrium has contributed greatly to paleoclimatology, paleo environment, paleo oceanology, archaeology as well as ...Spelean stalagmite dating using thermal ionization mass spectrometry (TIMS) on the basis of U Th disequilibrium has contributed greatly to paleoclimatology, paleo environment, paleo oceanology, archaeology as well as modern volcano magmatism studies. Results of our studies on stalagmite chronology are also reported in this paper.展开更多
The discovery of abrupt paleo\|climate change events and the prediction of environmental changes in the future time have raised an urgent request for high\|resolution paleo\|environmental records. This paper reviews t...The discovery of abrupt paleo\|climate change events and the prediction of environmental changes in the future time have raised an urgent request for high\|resolution paleo\|environmental records. This paper reviews the progress made in chronology and paleo\|environment of stalagmites from karst caves in China and presents some of the results of TIMS\|U\|series dating of stalagmites composed of secondary carbonates, taken from the Dongge, Longquan and Yamen karst caves in Libo County and the Qixing karst cave in Duyun, Guizhou Province, on a MAT\|262 mass spectrometer.展开更多
通过对青藏高原中南部天门洞石笋TM-18b进行230Th测年和稳定同位素测试,建立了倒三冰消期249.89—240.32 ka BP的石笋碳氧同位素记录。结合已发表的、发育在同一洞穴石笋的年代和同位素数据,对倒三冰消期石笋生长记录和同位素序列进行分...通过对青藏高原中南部天门洞石笋TM-18b进行230Th测年和稳定同位素测试,建立了倒三冰消期249.89—240.32 ka BP的石笋碳氧同位素记录。结合已发表的、发育在同一洞穴石笋的年代和同位素数据,对倒三冰消期石笋生长记录和同位素序列进行分析,发现天门洞石笋TM-18b和19TM-3在倒三冰消期弱季风区间分别沉积28.5 mm和13.9 mm,持续时间约6.5 ka和5.2 ka,表明倒三冰消期弱季风区间青藏高原气候较为温暖湿润。南极冰芯记录的大气CO_(2)、CH_(4)浓度及δD的上升和δ^(18)O_(atm)的下降,以及全球海平面的上升支持倒三冰消期弱季风区间青藏高原气候的回暖。弱季风区间石笋δ^(18)O记录显示季风降水贡献减少,说明冰川融水和/或西风水汽可能为区域降水增多、气候变湿提供了大量水汽。展开更多
新石器时代晚期(距今6.0~4.0 ka)对应着中国的五帝时代,是中国史前文明发展的关键阶段,重建这个时段的气候变化历史,对于我们理解人类文明演化至关紧要。来自重庆的4根全新世石笋δ^(18)O及其合成记录显示,在轨道尺度上东亚夏季风(East ...新石器时代晚期(距今6.0~4.0 ka)对应着中国的五帝时代,是中国史前文明发展的关键阶段,重建这个时段的气候变化历史,对于我们理解人类文明演化至关紧要。来自重庆的4根全新世石笋δ^(18)O及其合成记录显示,在轨道尺度上东亚夏季风(East Asian Summer Monsoon,EASM)跟随太阳辐射的变化趋势,从全新世早期到晚期逐渐减弱;以2.0 ka的时间段为单位进行线性趋势分析,在中全新世晚期6.0~4.0 ka B.P.期间的δ^(18)O值斜率绝对值最大,指示该阶段夏季风衰减速率最大。此外,长江中上游流域8条石笋δ^(18)O合成记录在轨道尺度和千年尺度上都与重庆地区石笋表现出相同的趋势,8.0~2.0 ka B.P.时段的斜率绝对值依次为0.053、0.136和0.084。这也得到了季风边缘区达理湖和公海湖孢粉记录的支持。长江中上游流域的石笋δ^(18)O值在千年尺度上也响应全新世夏季太阳辐射变化;8.0~6.0 ka B.P.时段夏季太阳辐射的变化速率分别为4.392、5.998和5.674,即在6.0~4.0 ka B.P.时段夏季太阳辐射衰减速率最快时,EASM强度在千年尺度上的减弱速率也是最大的。展开更多
The 8.2 and 4.2 ka BP abrupt climate events had significant impacts on Earth's climate system.However,the spatiotemporal pattern of these events remains ambiguous in the East Asian summer monsoon(EASM)region.In th...The 8.2 and 4.2 ka BP abrupt climate events had significant impacts on Earth's climate system.However,the spatiotemporal pattern of these events remains ambiguous in the East Asian summer monsoon(EASM)region.In this study,we collected thirteen previously published stalagmite δ^(18)O sequences from the EASM region to assess spatial and temporal patterns of the 8.2 and 4.2 ka BP events during the~8.7-7.7 ka BP and~4.7-3.7 ka BP periods,respectively.Our results reveal that highresolution stalagmite δ^(18)O sequences from nearby locations exhibit strong consistency during the Holocene,thus capturing regional patterns of climate variability.Sensitivity experiments indicate that the temporal resolution and geographical location significantly affect the ability of the stalagmite δ^(18)O sequences to record the 8.2 and 4.2 ka BP events.High-resolution stalagmite δ^(18)O records from both northern and southern China show a distinct positive δ^(18)O excursion corresponding with the 8.2 ka BP event,beginning at 8.23 ka BP and ending at 8.08 ka BP,thus lasting~150 yr,with an explained variance reaching~55% on centennial timescales.In contrast,there are significant north-south differences in the δ^(18)O signal during the period~4.26-3.97 ka BP,with a shift from negative to positive δ^(18)O values in northern China and a contrasting pattern in southern China.The application of the Monte Carlo empirical orthogonal function(MCEOF)method effectively reproduces the pronounced positive δ^(18)O excursion during the period~8.7-7.7 ka BP and exhibits fluctuations based on the long-term increase in δ^(18)O during the period~4.7-3.7 ka BP.The positive δ^(18)O excursion during the 4.2 ka BP event is primarily contributed by stalagmites from southern China,in particular the Dongge and Heshang Caves.Our study highlights the importance of using multiple high-resolution climate records to assess abrupt events both in space and time.展开更多
通过对云南司岗里洞石笋SGL1220的高精度230Th定年和高分辨率δ^(18)O分析,研究重建了西南季风区7.72—8.75 ka B.P.时段平均分辨为5年的石笋δ^(18)O记录。SGL1220石笋δ^(18)O变化指示区域夏季风降水(或者西南季风强度)变化,该记录清...通过对云南司岗里洞石笋SGL1220的高精度230Th定年和高分辨率δ^(18)O分析,研究重建了西南季风区7.72—8.75 ka B.P.时段平均分辨为5年的石笋δ^(18)O记录。SGL1220石笋δ^(18)O变化指示区域夏季风降水(或者西南季风强度)变化,该记录清晰记录了8.2 ka气候事件中西南季风变化过程。事件起于8.30 ka B.P.,止于8.10 ka B.P.,前后持续了约200年,事件呈现出“W”型的变化特征,两个季风极弱期分别出现在约8.22 ka B.P.和8.12 ka B.P.,对应8.2 ka弱季风事件的核心时段;SGL1220石笋记录的8.2 ka BP事件在定年误差范围内与东亚季风区的高分辨石笋氧同位素记录一致性地同步响应北大西洋降温变化,表现为亚洲夏季风显著减弱,支持“淡水输入”导致北大西洋区域显著降温,并通过大气遥相关的方式影响亚洲夏季风变化的驱动机制假说。展开更多
A multi-proxy quantum group signature scheme with threshold shared verification is proposed. An original signer may authorize a proxy group as his proxy agent. Then only the cooperation of all the signers in the proxy...A multi-proxy quantum group signature scheme with threshold shared verification is proposed. An original signer may authorize a proxy group as his proxy agent. Then only the cooperation of all the signers in the proxy group can generate the proxy signature on behalf of the original signer. In the scheme, any t or more of n receivers can verify the message and any t - 1 or fewer receivers cannot verify the validity of the proxy signature.展开更多
This paper proposes a threshold mult-proxy multi-signature scheme with share verification. In the scheme, a subset of original signers allows a designated group of proxy signers to sign on behalf of the original group...This paper proposes a threshold mult-proxy multi-signature scheme with share verification. In the scheme, a subset of original signers allows a designated group of proxy signers to sign on behalf of the original group. A message m has to be signed by a subset of proxy signers who can represent the proxy group. Then, the proxy signature is sent to the verifier group. A subset of verifiers in the verifier group can also represent the group to authenticate the proxy signature. In other words, some threshold values will be given to indicate the number of persons to represent a group to authorize the signing capability or to sign a message or to verify the proxy signature.展开更多
Multi-proxy signature schemes allow the original signer to delegate his/her signing power to n proxy signers such that all proxy signers must corporately generate a valid proxy signature on behalf of the original sign...Multi-proxy signature schemes allow the original signer to delegate his/her signing power to n proxy signers such that all proxy signers must corporately generate a valid proxy signature on behalf of the original signer. We first propose a multi-proxy signature scheme based on discrete logarithms and then adapt it to the elliptic curve cryptosystem. With the integration of self-certified public-key systems and the message recovery signature schemes,our proposed schemes have the following advan-tages:(1) They do not require the signing message to be transmitted,since the verifier can recover it from the signature;(2) The authentication of the public keys,verification of the signature,and recovery of the message can be simultaneously carried out in a single logical step;(3) No certificate is needed for validating the public keys. Further,the elliptic curve variant with short key lengths especially suits the cryptographic applications with limited computing power and storage space,e.g.,smart cards. As compared with the previous work that was implemented with the certificate-based public-key systems,the proposed schemes give better performance in terms of communication bandwidth and computation efforts.展开更多
基金supported by the National Natural Science Foundation of China(Nos.42074071,42274094,42261144739)the Shenzhen Science and Technology Program(No.KQTD20170810111725321)+2 种基金supported by the Taiwan University Core Consortiums Project(No.112L894202)the Higher Education Sprout Project of the Ministry of Education(No.112L901001)the National Science and Technology Council(No.111-2116-M-002-022-MY3)。
文摘The environmental magnetic proxies of stalagmites hold significant potential for reconstructing regional hydroclimate changes by revealing the content and grain size of magnetic particles within stalagmites.In this study,we present the contents and grain sizes of magnetic particles within a stalagmite SZ-1,from Shizhu Cave in southwestern China from 70.4 to 22.3 thousand years ago(ka)during the last glacial period.Specifically,the parameters IRM_(soft),soil-derived magnetic minerals,and ARM/SIRM(anhysteretic remanent magnetization/saturation isothermal remanent magnetization),the ratio of fine magnetic particles to total ferrimagnetic particles preserved in stalagmite SZ-1,indicate the fluctuation of regional precipitation.Obvious half-precessional cycles are evident in these two proxies,indicating that hydroclimatic variations in southwestern China may predominantly arise from the heat and moisture transported from tropical oceans.These variations are likely influenced by shifts in the Intertropical Convergence Zone and fluctuations in the Asian Summer Monsoon.
文摘: Comprehensive studies on a stalagmite from the Panlong cave, Guilin, have shown that the isotopic records and sedimentary characteristics can reflect the changes of both palaeotemperatures and palaeorainfall, that is to say, it is possible to get some information about the changes in climate of the area from the speleothem. The results suggest that: (1) the Younger Dryas event might have persisted in the area from 11 300 to 10 800 a B.P.; (2) from 9000 to 7000 a B.P., the climate got warmer and wetter, and the summer monsoon was gradually enhanced; (3) from 7000 to 4500 a B.P., the climate was warm and wet, and the summer monsoon prevailed; and (4) from 4500 a B.P. on, the summer monsoon was weakened and the modern climate pattern appeared, but there were several cold and dry periods, namely, from 4000 to 2500 a B.P., ca. 2400 a B.P. and < 1000 a B.P.
文摘In this paper the authors report a preliminary study on a Holocene stalagmite from Shihua Cave in Southwest Beijing.The result shows that the thickness of annual growth layers which is defined by annual deposit hiatuses preserve changes with precipitation. In light with the thickness of annual layers the authors reconstruct the climatic variation history of the last 2300 years in Beijing area.The climatic patterns seems to reappear irregularly on millennium to decade scales in the last 1000 years. The stable isotopic sequence interprets that the climate and environment in Beijing could be separated into two stages in the late Holocene: the monsoon was strong and the environment was wet in the former stage and in the latter stage the monsoon was weak and the environment was dry. The annual layers and oxygen isotope could be taken as natural signals and carbon isotope as a comprehensive signal containing the natural information and the information of anthropogenic activity.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No. XDA11010401)the National Natural Science Foundation of China (Grant No. NSFC41375085)
文摘The stalagmite δ18O record is known to be associated with the climate, but the specifics of the relationship remain unclear. It may not represent variation in air temperature or precipitation, but instead reflect integral changes of monsoon circulation, especially water vapor sources(the so-called "circulation effect"). Since large-scale atmospheric-oceanic modes such as the Atlantic Multidecadal Oscillation(AMO), Pacific Decadal Oscillation(PDO), and North Atlantic Oscillation(NAO) exert significant effects on Asian monsoon, in this paper the authors investigate the relationships of the East Asian stalagmite δ18O record with these modes. The last three centuries form the focus of our study, for which the authors use reconstructed as well as instrumental data. Considering the impacts of human activity, our analysis is conducted with respect to two periods—the pre- and post-industrial periods. The results show significant lead-lag connections: a positive correlation peaks when the PDO leads East Asian stalagmite δ18O by 3 years, which is persistent over the past 300 years; while the relationships of the AMO and NAO with the East Asian stalagmite δ18O record show significant differences in the post-industrial relative to the pre-industrial period. This implies that the East Asian stalagmite δ18O record may primarily reflect the PDO signal.
文摘Spelean stalagmite dating using thermal ionization mass spectrometry (TIMS) on the basis of U Th disequilibrium has contributed greatly to paleoclimatology, paleo environment, paleo oceanology, archaeology as well as modern volcano magmatism studies. Results of our studies on stalagmite chronology are also reported in this paper.
文摘The discovery of abrupt paleo\|climate change events and the prediction of environmental changes in the future time have raised an urgent request for high\|resolution paleo\|environmental records. This paper reviews the progress made in chronology and paleo\|environment of stalagmites from karst caves in China and presents some of the results of TIMS\|U\|series dating of stalagmites composed of secondary carbonates, taken from the Dongge, Longquan and Yamen karst caves in Libo County and the Qixing karst cave in Duyun, Guizhou Province, on a MAT\|262 mass spectrometer.
文摘新石器时代晚期(距今6.0~4.0 ka)对应着中国的五帝时代,是中国史前文明发展的关键阶段,重建这个时段的气候变化历史,对于我们理解人类文明演化至关紧要。来自重庆的4根全新世石笋δ^(18)O及其合成记录显示,在轨道尺度上东亚夏季风(East Asian Summer Monsoon,EASM)跟随太阳辐射的变化趋势,从全新世早期到晚期逐渐减弱;以2.0 ka的时间段为单位进行线性趋势分析,在中全新世晚期6.0~4.0 ka B.P.期间的δ^(18)O值斜率绝对值最大,指示该阶段夏季风衰减速率最大。此外,长江中上游流域8条石笋δ^(18)O合成记录在轨道尺度和千年尺度上都与重庆地区石笋表现出相同的趋势,8.0~2.0 ka B.P.时段的斜率绝对值依次为0.053、0.136和0.084。这也得到了季风边缘区达理湖和公海湖孢粉记录的支持。长江中上游流域的石笋δ^(18)O值在千年尺度上也响应全新世夏季太阳辐射变化;8.0~6.0 ka B.P.时段夏季太阳辐射的变化速率分别为4.392、5.998和5.674,即在6.0~4.0 ka B.P.时段夏季太阳辐射衰减速率最快时,EASM强度在千年尺度上的减弱速率也是最大的。
基金was supported by the National Program on Key Basic Research Project of China(Grant No.2022YFF0801102)the National Natural Science Foundation of China(Grant No.42130511)+2 种基金the Swedish Research Council(Vetenskapsr?det,Grant No.2023-00605)the Marianne and Marcus Wallenberg Foundation(Grant No.MMW 2022-0114)the Centre for Advanced Study(CAS)at the Norwegian Academy of Science and Letters(2024/2025yr)。
文摘The 8.2 and 4.2 ka BP abrupt climate events had significant impacts on Earth's climate system.However,the spatiotemporal pattern of these events remains ambiguous in the East Asian summer monsoon(EASM)region.In this study,we collected thirteen previously published stalagmite δ^(18)O sequences from the EASM region to assess spatial and temporal patterns of the 8.2 and 4.2 ka BP events during the~8.7-7.7 ka BP and~4.7-3.7 ka BP periods,respectively.Our results reveal that highresolution stalagmite δ^(18)O sequences from nearby locations exhibit strong consistency during the Holocene,thus capturing regional patterns of climate variability.Sensitivity experiments indicate that the temporal resolution and geographical location significantly affect the ability of the stalagmite δ^(18)O sequences to record the 8.2 and 4.2 ka BP events.High-resolution stalagmite δ^(18)O records from both northern and southern China show a distinct positive δ^(18)O excursion corresponding with the 8.2 ka BP event,beginning at 8.23 ka BP and ending at 8.08 ka BP,thus lasting~150 yr,with an explained variance reaching~55% on centennial timescales.In contrast,there are significant north-south differences in the δ^(18)O signal during the period~4.26-3.97 ka BP,with a shift from negative to positive δ^(18)O values in northern China and a contrasting pattern in southern China.The application of the Monte Carlo empirical orthogonal function(MCEOF)method effectively reproduces the pronounced positive δ^(18)O excursion during the period~8.7-7.7 ka BP and exhibits fluctuations based on the long-term increase in δ^(18)O during the period~4.7-3.7 ka BP.The positive δ^(18)O excursion during the 4.2 ka BP event is primarily contributed by stalagmites from southern China,in particular the Dongge and Heshang Caves.Our study highlights the importance of using multiple high-resolution climate records to assess abrupt events both in space and time.
文摘通过对云南司岗里洞石笋SGL1220的高精度230Th定年和高分辨率δ^(18)O分析,研究重建了西南季风区7.72—8.75 ka B.P.时段平均分辨为5年的石笋δ^(18)O记录。SGL1220石笋δ^(18)O变化指示区域夏季风降水(或者西南季风强度)变化,该记录清晰记录了8.2 ka气候事件中西南季风变化过程。事件起于8.30 ka B.P.,止于8.10 ka B.P.,前后持续了约200年,事件呈现出“W”型的变化特征,两个季风极弱期分别出现在约8.22 ka B.P.和8.12 ka B.P.,对应8.2 ka弱季风事件的核心时段;SGL1220石笋记录的8.2 ka BP事件在定年误差范围内与东亚季风区的高分辨石笋氧同位素记录一致性地同步响应北大西洋降温变化,表现为亚洲夏季风显著减弱,支持“淡水输入”导致北大西洋区域显著降温,并通过大气遥相关的方式影响亚洲夏季风变化的驱动机制假说。
基金Project supported by the National Basic Research Program of China (973 Program) (Grant No 2007CB311100)the National High Technology Research and Development Program of China (Grant Nos 2006AA01Z419 and 20060101Z4015)+4 种基金the Major Research plan of the National Natural Science Foundation of China (Grant No 90604023)2008 Scientific Research Common Program of Beijing Municipal Commission of Education The Scientific Research Foundation for the Youth of Beijing University of Technology (Grant No 97007016200701)the National Research Foundation for the Doctoral Program of Higher Educationof China (Grant No 20040013007)the National Laboratory for Modern Communications Science Foundation of China (GrantNo 9140C1101010601)the Doctor Scientific Research Activation Foundation of Beijing University of Technology (Grant No 52007016200702)
文摘A multi-proxy quantum group signature scheme with threshold shared verification is proposed. An original signer may authorize a proxy group as his proxy agent. Then only the cooperation of all the signers in the proxy group can generate the proxy signature on behalf of the original signer. In the scheme, any t or more of n receivers can verify the message and any t - 1 or fewer receivers cannot verify the validity of the proxy signature.
基金Supported by the National Natural Science Foundation of China (No.10471152).
文摘This paper proposes a threshold mult-proxy multi-signature scheme with share verification. In the scheme, a subset of original signers allows a designated group of proxy signers to sign on behalf of the original group. A message m has to be signed by a subset of proxy signers who can represent the proxy group. Then, the proxy signature is sent to the verifier group. A subset of verifiers in the verifier group can also represent the group to authenticate the proxy signature. In other words, some threshold values will be given to indicate the number of persons to represent a group to authorize the signing capability or to sign a message or to verify the proxy signature.
基金Project (No. 94-2213-E-182-019) supported by the National Science Council, Taiwan, China
文摘Multi-proxy signature schemes allow the original signer to delegate his/her signing power to n proxy signers such that all proxy signers must corporately generate a valid proxy signature on behalf of the original signer. We first propose a multi-proxy signature scheme based on discrete logarithms and then adapt it to the elliptic curve cryptosystem. With the integration of self-certified public-key systems and the message recovery signature schemes,our proposed schemes have the following advan-tages:(1) They do not require the signing message to be transmitted,since the verifier can recover it from the signature;(2) The authentication of the public keys,verification of the signature,and recovery of the message can be simultaneously carried out in a single logical step;(3) No certificate is needed for validating the public keys. Further,the elliptic curve variant with short key lengths especially suits the cryptographic applications with limited computing power and storage space,e.g.,smart cards. As compared with the previous work that was implemented with the certificate-based public-key systems,the proposed schemes give better performance in terms of communication bandwidth and computation efforts.
