不出力窃听

您担心您的截住不相当一样高保真，象您希望？ 不能捉住其他人民细节’电子交谈？ 您窃听使您失望？ 欢迎到现代偷听者的不幸的世界!

计算和信息学家埃里克Cronin， Micah Sherr和宾夕法尼亚大学的马特火焰调查了当前窃听的工具的可靠性并且发现他们缺乏。 “获得`高保真度的’抄本比早先假设”，坚硬他们在安全和网络(2008年， 3， 103-113)国际定期刊物的一个即将到来的问题说。 他们增加那，甚而在高度有利情况被暗中侦察的那些可能阻拦窃听的技术和防止消息准确被重建。

系统实验报告不规则性的大约三分之一，和几乎半不正确地解释送的党选择的隐蔽文本

队测试了开放来源窃听的工具，并且买得到的包裹，包括Bro， Chaosreader，飘渺，打鼾， tcpick、tcptrace、tcpflow、CommView、NetworkActiv和Sniffem。

他们指出那，不同于加密或steganography (增加一则秘密消息艺术到图象)，防止被拦截的通信的准确重建(它是否是电子邮件、立即消息或者VoIP)，不要求沟通的党的参与-我们将称他们Alfie和Bess。 的确，简单的单边的窃听的对抗措施手段电子通讯在Alfie和Bess不可能由试图的某人重建与100%保真度(例如代理克拉克)暗中侦察。

有意味互联网的几物产没错误窃听不是几乎一样容易，象电影编剧会让我们相信。 首先，有许多不同的组分到所有特定通信连接。 许多发生在Alfie和Bess的互联网之间通信设备调动的控制被分权。 而且，当转移时通信数据它使用“最佳的努力”方法做，与一个可靠和lossless方法相对，造成被重新安排的，被复制的或者失去的小包。 这些网络作用使它难为了克拉克能察觉通信，以与Alfie和Bess相似的方式。

数据流程一直改变，经常不对称地，在数据包衰退和流程做得到把柄困难在沿同样铜丝和光纤链接来回寻址的亿万小包之中。 另外，有二义性在通信协议，他们被实施，并且的方式怎么配置他们，再手段重建一次电子交谈从有些各种各样的零零点点与Alfie的是一致的，并且Bess’解释是困难的。 Finally, because there is an essential lack of sender and receiver authentication, there is no way for Clark to know for certain that any given thread of e-chat was sent by Alfie or Bess.

Moreover, if Alfie and Bess, or yet another third party, Evelyn, deliberately add confusion into the setup - either physically, using different broadcast frequencies on WiFi, or through software obfuscation - to rebuff the eavesdropper, then even without encryption Clark is all but locked out.

Without using any confusion techniques, all but one of the eavesdropping packages were able to intercept and reconstruct the messages accurately. However, as soon as confusion software was employed, all eavesdropping systems failed. The two simple confusion protocols against which the eavesdropping software was tested were MAC (as in the Media Access Control address that uniquely identifies devices connecting to a switch or hub) and TTL (time-to-live, the variable that drops packets if they stay in transit too long). In MAC confusion, the address is spoofed or changed obscuring the source of any given packet, while exploiting TTL involves ensuring the packet last long enough to get from Alfie to Bess and vice versa but times out before Clark can grab it.

Traditional wisdom has held that eavesdropping is sufficiently reliable as long as the communicating parties do not participate in a bilateral effort to conceal their messages,” the researchers say, “We have demonstrated that even in the absence of cooperation between the communicating endpoints, reliable internet eavesdropping is more difficult than simply capturing packets.”

For more on the current debacle regarding National Security Agency allegedly eavesdropping on your email check out this security post from Surveillance State’s Chris Soghoian.