In a large metal bowl cream, take 1 stick of butter with 2
cups of sugar. Ok, so we are not going to talk about chocolate chip, oatmeal,
or sugar cookies. Today, we are going to discuss cookies of the technological
variety. Unless you’ve been asleep for the last 10 years, you’ve probably heard
the term cookies and how they’re used by web sites and browsers. In this
article, we’ll look at what’s inside of them and how they work.

What’s a cookie?

A cookie is a small text file that a web site stores on your
PC’s hard drive. The cookie stores info about your specific visit to that site.
But don’t panic quite yet. Cookies are NOT programs and therefore cannot run
like programs. web sites can be programmed to read data from the cookies and
write information to them, but the cookies themselves don’t do anything.

There are different types of cookies. A first-party cookie
stores information only from the website you are on. A third-party cookie
stores information for another website than the one you’re currently viewing but
is hosted by the first-party one. websites sometimes use third-party for
advertisers.

Cookies make it easy for web designers to personalize sites.
They also can be used for authentication purposes. For example, when you surf
to TechRepublic, you’ll notice that your name appears at the top of the site
every time after you log in. That’s because there’s a cookie stored on your
workstation that stores your TechRepublic login information. Your TechBooks
information is stored in a separate cookie because the TechBooks access
information comes from a third party, Books 24×7.

Cookies are a hot topic because of all of the concern about
privacy and security. Many anti-spyware programs target and eliminate tracking
cookies used by third parties as part of their battle against spyware. Additionally,
cookies can be a security concern in an environment where you have multiple
machines. For example, if you walk away from your computer, a co-worker can
access your TechRepublic account by simply sitting at your machine.

Where’s my cookie jar?

You can find the cookies on your system by going to the
Documents And Settings folder on your Windows XP workstation. Other versions of
Windows and other operating systems will store cookies in other locations, but
for the purposes of this article, I’m just going to concentrate on XP. In the
Documents And Settings folder, you’ll see a set of user names. These are the
profiles that can access your system.

Double-click a folder to open it. You’ll see another set of
folders. Cookies are stored in the Cookies folder. If you open that one, you’ll
probably be shocked to see the number of files in there. They represent cookies
from all of the web sites you’ve ever visited, along with partner sites.

Firefox, Mozilla, Netscape, Opera, and other web browsers
will store cookies in different places. Therefore, if you’re using another web
browser, you should become familiar with where they store their cookies if you
want to clear or view them. For example, you can view and clear cookies in
Firefox by clicking Tools | Options | Privacy | Cookies.

You can download special extensions for Firefox that help
you gain control over cookies. To do so, just visit the Firefox
Extensions web site.

What’s in a cookie?

Just as edible cookies are baked according to a specific
recipe, so are Internet cookies. There are certain things that are found in
every Internet cookie:

  • Name: The name of the cookie
  • Value: The information the cookie
    is storing
  • Expiration Date: The date after
    which the cookie’s information isn’t valid
  • Path: The path on the domain
    where the cookie information goes
  • Domain: The name of the domain
    that is issuing the cookie
  • Secure connection: This setting indicates
    whether the browser must communicate with the site over a secure
    connection such as https://

If you try to edit a cookie with a text editor, you may
notice that it doesn’t make much sense. For example, here’s a cookie off of my
machine:

SRCHUID

V=1&GUID=D9C9BBB79D7E48FC97FAF84CD123AF5E

search.msn.com/

1024

79CAF3984

30458696

693120992

22778098

*

SRCHUSR

AUTOREDIR=0&GEOVAR=-1&DOB=20060420

search.msn.com/

1024

3712463808

30513523

694652392

29723498

*

Doesn’t make a lot of sense to a human, but when passed to a
web site, it contains a lot of information.

How do cookies work?

web sites are programmed to read and write cookies to your
computer through your web browser. Using simple http protocols, the site
transmits the cookie to your browser. It stays in memory as long as the browser
is open and on that site. If the expiration date hasn’t passed and you leave
the site or close the browser, the browser writes it to disk.

The next time you visit the site, it will ask the browser to
check to see if a cookie exists for the site. If it does, the browser reads it
and passes the stored information to the site. If not, a new cookie is created.