Windows 7 : Configuring Internet Explorer Security - Enhancing Your Browsing Privacy (part 3) - Enhancing Online Privacy by Managing Cookies

Enhancing Online Privacy by Managing Cookies

A cookie is a small text file that’s stored on your computer. Websites use them to “remember” information about your session at that site: shopping cart data, page customizations, usernames, passwords, and so on.

No other site can access your cookies, so they’re generally safe and private under most—but definitely not all—circumstances. To understand why cookies can sometimes compromise your privacy, you have to understand the different cookie types that exist:

• Temporary cookie— This type of cookie lives just as long as you have Internet Explorer running. Internet Explorer deletes all temporary cookies when you shut down the program.

• Persistent cookie— This type of cookie remains on your hard disk through multiple Internet Explorer sessions. The cookie’s duration depends on how it’s set up, but it can be anything from a few seconds to a few years.

• First-party cookie— This is a cookie set by the website you’re viewing.

• Third-party cookie— This is a cookie set by a site other than the one you’re viewing. Advertisers that have placed an ad on the site you’re viewing create and store most third-party cookies.

These cookie types can compromise your privacy in two ways:

• A site might store personally identifiable information—your name, email address, home address, phone number, and so on—in a persistent first- or third-party cookie and then use that information in some way (such as filling in a form) without your consent.

• A site might store information about you in a persistent third-party cookie and then use that cookie to track your online movements and activities. The advertiser can do this because it might have (for example) an ad on dozens or hundreds of websites, and that ad is the mechanism that enables the site to set and read their cookies. Such sites are supposed to come up with privacy policies stating that they won’t engage in surreptitious monitoring of users, they won’t sell user data, and so on.

To help you handle these scenarios, Internet Explorer implements a privacy feature that gives you extra control over whether sites can store cookies on your machine. To check out this feature, select Internet Explorer’s Tools, Internet Options command, and then display the Privacy tab, shown in Figure 4. You set your cookie privacy level by using the slider in the Settings group.

You set your cookie privacy level by using the slider in the Settings group. First, let’s look at the two extreme settings:

• Accept All Cookies— This setting (at the bottom of the slider) tells Internet Explorer to accept all requests to set and read cookies.

• Block All Cookies— This setting (at the top of the slider) tells Internet Explorer to reject all requests to set and read cookies.

In between are four settings that offer more detailed control. Table 1 shows you how each setting affects the three types of privacy issues.

Here are some notes about the terminology in this table:

• Restricted means that Internet Explorer doesn’t allow the site to set a persistent cookie, just a temporary one.

• A compact privacy policy is a shortened form of a privacy policy that can be sent along with the cookie and that can be read by the browser.

• Implicit consent means that one or more pages leading up to the cookie warned you that your personally identifiable information would be used and you agreed that it was okay.

• Explicit consent means that the page that reads the cookie warned you that your personally identifiable information would be used and you agreed that it was okay.

That’s fine on a broad level, but you can fine-tune your cookie management by preventing specific sites from adding cookies to your computer. For example, you can prevent Google from tracking your search activity by preventing it from adding cookies to your PC. You might also want to block ad sites such as doubleclick.net.

Here are the steps to follow in Internet Explorer to block a site from adding cookies: