用椭圆曲线实现的Applet代理签名方案

在网络信息系统安全管理中,使用签名Applet访问客户端资源能更灵活地扩展网络应用。然而在现行的Applet签名方案中,由于Jar包使用常规的签名方法,使客户端仅允许指定安全服务器中的Applet签名程序访问本机资源,而其他服务器的Applet程序即使被证明是可信的也无法实现同样的功能。这样的设置尽管保证了客户端访问的安全性,却使得网络分布性资源使用的效率无法提高,限制了网络应用。针对于此,该文提出了用椭圆曲线实现的Applet代理签名新方案,并对该方案的安全性进行了分析。     

签名笔迹鉴定方法与鉴定意见标准化探究

签名笔迹是笔迹的一种特殊类型,具有特殊的分类,因而签名笔迹鉴定案件也具有一定的特殊性。这些决定了签名笔迹案件的鉴定具有特定的方法与要点。除了签名笔迹案件的鉴定方法外,签名笔迹鉴定意见的标准化也是值得探究的一个方面。     

伪装签名检验初探

伪装签名是一种签名造假手段,其目的是通过否认签名是自己所写,非法占有他人财物或逃避责任。伪装签名笔迹貌似正常,但受不同伪装手段的影响,笔迹会发生各种变化,因而检验难度较大。检验伪装签名时,鉴定人要解放思想,客观看待笔迹发生的变化,选用正确的检验方法,客观全面地选择笔迹特征,适时补充笔迹样本,条件具备时还应充分利用案情。     

Tropane ethyl esters in illicit cocaine: isolation, detection, and determination of new manufacturing by-products from the clandestine purification of crude cocaine base with ethanol

Seven ethyl homologues of known tropane esters have recently been detected as impurities in the gas chromatographic signature profiles of authentic Peruvian illicit cocaine base and hydrochloride exhibits. Peruvian cocaine base processors are now known to use ethanol for the purification of crude cocaine base. This process is referred to as the "base lavada" or "washed base" process and is a recent substitute method for the potassium permanganate oxidation purification methodology. Seven ethyl ester homologues were formed in illicit cocaine from the transesterification of known tropane methyl esters or possibly ethyl esterification of their respective tropane C-2 carboxylic acids in the presence of ethanol. Exhibits containing these compounds were subjected to gas chromatographic-mass spectrometric analyses to determine their identity and were subsequently synthesized to verify their structures. Quantitative determinations were obtained from ion-pair chromatography isolation followed by gas chromatography with flame ionization detection. Specifically, hexanoylecgonine ethyl ester, cocaethylene, cis-cinnamoylecgonine ethyl ester, trans-cinnamoylecgonine ethyl ester, 3',4',5'-trimethoxybenzoylecgonine ethyl ester, cis-3',4',5'-trimethoxycinnamoylecgonine ethyl ester, and trans-3',4',5'-trimethoxycinnamoylecgonine ethyl ester were detected and characterized. When present, these compounds were detected at levels ranging from 8.6 x 10(-4) to 9.3 x 10(-1)% relative to cocaine.     

Injuries to law enforcement officers: the backface signature injury

In today's law enforcement community, one of the most vital tools an officer can possess is personal body armor. However, a recent Department of Justice investigation has raised important questions regarding the protection actually afforded officers through the use of personal body armor, and the current test methods used to assess the armor. Test results show that most Zylon-containing vests showed deformations in excess of the 0101.04 Standard's 44 mm backface signature limit. Such increased deformation can lead to serious injuries, including backface signature injuries, which have occurred in the field. Although the vest is successful in containing the round, it is not effectively dissipating the energy enough to prevent large amounts of vest deformation at the area of impact. Therefore, open, penetrating wounds occur even though the bullet did not penetrate the vest. The objective of the current study was to further define the backface signature injury through the use of case studies and laboratory experiments. Following the case study investigation, backface signature testing was conducted using a clay medium based on the NIJ 0101.04 Standard. The final component of this research involved the use of post-mortem human specimens (PMHS) for further investigation of the backface signature injury. Although the underlying cause of backface signature injuries is unknown, energy density is likely to play a role in the mechanism. Energy density (E/a) is defined as the energy per unit area and has been previously used in less lethal skin penetration research. Further research into the underlying causes of backface signature injuries is necessary. In addition to armor testing, the study of law enforcement personnel who have been shot while wearing soft body armor is also a valuable tool for determining the effectiveness of certification standards. Finally, it is important for medical personnel to recognize the backface signature injury and document this as a type of injury separate from blunt trauma or penetrating trauma behind armor injuries. Detailed knowledge of the injury, including the depth of the wound, would be beneficial to the scientific community.