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An Introduction to Cookies
Cookies are messages given to a
Web browser by a
Web server.
The main purpose of a cookie is to identify users and possibly
prepare customized Web pages or to save site login information for
you. When you enter a
Web site
using cookies, you may be asked to fill out a form providing such
information as your name and interests. This information is packaged
into a cookie and sent to your Web browser, which stores it for later
use. The next time you go to the same Web site, your browser will
send the cookie to the Web server. The message is then sent back to
the server each time the browser requests a page from the server.
A Web server has no memory so the
hosted Web site you are visiting transfers a cookie file of the
browser on your computer's hard disk so that the Web site can
remember who you are and your preferences. This message exchange
allows the Web server to use this information to present you with
customized Web pages. So, for example, instead of seeing just a
generic welcome page you might see a welcome page with your name on
it.
Types of Cookies:
session
cookie
Also called a transient cookie, a cookie that is erased when you close the Web browser. The session cookie is stored in
temporary memory and is not retained after the browser is
closed. Session cookies do not collect information from yourcomputer. They typically will store information in the
form of a session identification that does not personally
identify the user.
persistent cookie
Also called a permanent cookie, or a stored cookie, a cookie
that is stored on your hard drive until it expires
(persistent cookies are set with expiration dates) or until you delete the cookie. Persistent cookies are used to collect
identifying information about the user, such as Web surfing
behavior or user preferences for a specific Web site.
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Key Terms To
Understanding Cookies:
cookie
A message given to a Web browser by a Web server. The browser stores
the message in a text file. The message is then sent back to the
server each time the browser requests a page from the server.
session cookie
Also called a transient cookie, a cookie that is erased when you close the Web browser. The session cookie is stored in
temporary memory and is not retained after the browser is closed.
persistent cookie
Also called a permanent cookie, or a stored cookie, a cookie that is
stored on your hard drive until it expires (persistent cookies
are set with expiration dates) or until the user deletes the cookie.
Web server
A computer that delivers (serves up) Web pages. Every Web server has
an IP address and possibly a domain name.
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What Information Does a Cookie Store?
For the most part a cookie will contain a string of text that contains
information about the browser. To work, a cookie does not need to know
where you are from, it only needs to remember your browser. Some Web sites do
use cookies to store more personal information about you. However, this can
be done only if you yourself have provided the Web site with that personal
information. Legitimate Web sites will encrypt this personal information
stored in the cookie to prevent unauthorized usage by another party with
access to your cookie folder.
What About Malicious Cookies?
Cookies normally do not compromise security, but there is a growing
trend of malicious cookies. These types of cookies can be used to store and
track your activity online. Cookies that watch your online activity are
called malicious or tracking cookies. These are the bad cookies to watch
for, because theytrack you and your surfing habits, over time, to build a
profile of your interests. Once that profile contains enough information
there is a good chance that your information can be sold to an advertising
company who then uses this profile information to target you with interest
specific adverts. Many
antivirus programs today will flag suspicious
spyware or
adware cookies when scanning your system for viruses.
Viewing & Removing Cookies
Cookies are stored by the Web browser on your system's hard drive, and you
can view them to see which Web sites that you visit are associated with your
cookie files.
If using
Internet Explorer 7
(IE7), for example you select Tools then
choose Internet Options. On the general tab you will see a
section titled Browser History. Click Settings then
choose View Files.
This will open up a Windows Explorer
window that lists all your temporary Internet files, including your
cookies. Each cookie will be identified by a site URL making it easy
to determine which cookies you trust and want to keep and which you
don't recall from visiting a Web site and would delete.
To change your cookie settings in IE7,
to go back into Tools then
choose Internet Options. On the Privacy tab you will see a
slider bar which you can move to adjust the level at which your
browser accepts cookies. Low for example blocks third-party cookies
that do not have a compact privacy policy and restricts third-party
cookies that save information that can be used to contact you
without your consent. Medium High will do the same but also block
first-party cookies that save information about you. Other privacy
options you can choose would be to accept all cookies or to block
all cookies as well.
If you're using a browser other than
Internet Explorer, you can visit the following cookie pages on each browser
Web site to find out how to manage your cookies when using Firefox, Opera,
or Safari.
First and Third-Party Cookies
When choosing a privacy setting in your browser, two terms you will see are
"first-party cookies" and "third-party cookies". First party cookies are
those cookies that originate from (or be sent to) the Web site you're
currently viewing. These types of cookies usually will contain information
about your preferences for that particular Web site. These cookies are
usually Third-party cookies originate from (or will be sent to) a Web site
that is not the site you are visiting. For example, if the Web site you are
on using third-party advertising those third-party advertising Web sites may
use a cookie to track your Web habits for marketing purposes.
While some may simply choose to block all
cookies, it can make Web surfing difficult if you do this. For example if
you shop online, many e-commerce shopping carts that have been implemented
with cookies will not work. Sites you frequently visit which enable you to
personalize content also will not show your preferences when you visit if you delete
or disable that cookie.
Most cookies, despite some misconceptions, are
legitimate files and will not invade your privacy. Once you get in the habit
of reviewing the cookies associated with your browser and manage them on
your own by way of deleting malicious cookies or trying different browser
privacy settings, you can still keep the good cookies that make surfing a
breeze, yet keep the bad cookies that may be tracking your surfing habits off your system.
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Did You Know...
The name cookie derives from
UNIX objects called magic cookies. These are tokens that are
attached to a user or program and change depending on the areas
entered by the user or program. |
