8-11 我认识你吗？（在线收听）

Do I Know You?

With computer security threats lurking around every electronic corner it is no wonder that so many online activities, from signing into your e-mail to checking your bank account, require a secure log-in with a password. But passwords can be stolen or forgotten, and most of us are not about to shell out¹ for a high-tech retinal² scanner³. So Israeli scientists in Haifa⁴ have created a program that lets a computer recognize you as its rightful user based simply on the way you type.

The human brains behind this artificial brain are two undergraduate students. They came up with the idea of a program that recognizes users by their keystrokes and took it to a professor of computer science. The professor and other scientists realized that any standard computer already monitors the time it takes a user to press and release a key. Their innovation was to create a program that records the details of keystroke timing and turns them into a distinctive⁵ user profile. Variables such as the length of your fingers, the size of your hands, your fine motor skills, your knowledge of the keyboard, and your fluency in the language being typed all affect your keystroke rate and pattern and define your rhythm on the keyboard as uniquely your own.

If the person working on the computer fits your profile, the program will signal a positive ID; if the program senses a mismatch, it could be used to block access to sensitive files. The great appeal of this security system is that it does not require the user to do anything out of the ordinary. You go about business as usual while the computer does all the work. “One can obviously deliberately⁶ type in a way that differs from how one normally would, but it’s really very hard to type like somebody else,” the scientists say. “This program picks out superimposed⁷ patterns unique to an individual user.”

The researchers tested the program by allowing five authorized⁸ users to type simple sentences, permitting the system to learn their typing habits. They then asked the five authorized users and 30 mock⁹ attackers to type out answers to simple open? ended questions such as “ What did you do today?” as well as a specific letter sequence: “To be or not to be. That is the question.” Both groups were then allowed to type whatever they wished. Within a few minutes of typing, the program had collected enough data to recognize authorized users 95 percent of the time and to block attackers in 99 percent of the test sessions.

This security system can also be equipped with an alert function to notify the authorized user when an attacker attempts to get access to his or her account. The scientists are also working on a companion program that would recognize patterns in computer mouse usage, which could prevent a stranger from clicking on folders to view sensitive files. In fact, there’s no reason why this approach must be limited to computers. The more complex the interaction, the easier it is for the system to identify someone because the variability is so great. The scientists aim to develop a program that allows a car to recognize its owner based on characteristic patterns of braking¹⁰, accelerating¹¹, signaling, turning, and other essential driving actions.

注释：

1. shell out  交(款)，付(款)

2. retinal [`retInEl] a.  视网膜的，视网膜上的

3. scanner [5skAnE] n.  扫描设备

4. Haifa [5haifE] 海法 [以色列港市]

5. distinctive [dis5tiNktiv] a.  特别的，有特色的

6. deliberately [dI5lIbErEtlI] ad.  故意地，蓄意地

7. superimposed [7sju:pErim5pEuzd] a.  叠置的，重叠的，附加上的

8. authorized [5C:WEraIzd] a.  经授权的，经委托的

9. mock [mCk] a.  假的，假装的

10. brake [breik] vi.  刹车

11. accelerate [Ak5selEreit] vi.  加速，增速

我认识你吗？

在计算机和网络的世界里，对于安全的威胁几乎无处不在。难怪那么多的在线活动都要求输入密码进行安全登录，从进入你的电子邮箱到检查你的银行账户。但是密码可以被窃或者被遗忘，而多数人还没有做好为高技术的视网膜扫描仪花一大笔钱的准备。所以，以色列海法市的科学家开发了一个程序，使计算机只需仅仅根据你的打字方式就能识别你是否是合法用户。

这个人工智能程序的发明者是两个本科学生。他们开发出一个根据键盘击键模式识别使用者的程序，并把它拿去给一位计算机科学教授看。教授和同行科学家知道，所有标准配置的计算机在用户敲击键盘时已经对其同时进行了监控。他们的发明是编写一个程序，记录下键盘输入的时间细节，并将其转换成个人特有的用户档案。各种变量，诸如你手指的长度、手的大小、细微的指法特点、键盘知识以及对输入语言的熟练程度，都会影响你的键入速度、模式，并决定你独有的输入节奏。

如果一个人的电脑操作习惯符合你的档案资料，那么程序就会发出一个信号表明身份验证已获通过；如果程序判断出不相符合，它就会阻止这个人接触你的机密文档。这个安全系统一个很大的诱人之处在于，它不要求使用者多做任何操作。你就像平常一样工作，而计算机会完成它该干的识别工作。“一个人显然可以故意改变他一贯的键入方式，但是想要模仿其他人的键入方式却是非常困难的，”科学家们说。“这个程序辨识并储存特定使用者所特有的键入模式，(并将其与每一位使用者的键入模式相比较，以确定是否相符。)”

研究人员对程序进行了测试。他们准许5名授权使用者键入简单的句子，让系统了解他们的键入习惯；然后请5名授权使用者和30个模拟攻击者键入一些简单开放式问题（如“你今天做了些什么事情？”）的答案，并让他们键入一指定的句子——“生还是死，问题就在这里。”两组测试者随后被允许任意键入他们想要输入的内容。在键盘操作的短短几分钟内，识别程序已收集到足够数据，能够识别授权使用者和阻截攻击者，准确率分别达到95％和99％。

这个安全系统还可以配备报警功能。当攻击者试图进入授权使用者的账户时，该功能将向其发出通知。科学家们还在开发一个伴侣程序，用来识别计算机鼠标操作模式，以防止陌生人通过点击文件夹看到机密文档。实际上，这种识别程序的原理应当不仅仅只局限于计算机。由于变量如此之大，因此，人和机器的相互作用越复杂，系统就越容易识别用户。科学家有志于开发一个程序，使汽车能够根据刹车、加速、指示灯操作、转弯以及其他的基本驾驶风格来识别自己的主人。