An HTTP cookie (also called web cookie, Internet cookie, browser cookie, or simply cookie) is a small piece of data stored on the user’s computer by the web browser while browsing a website. Cookies were designed to be a reliable mechanism for websites to remember stateful information (such as items added in the shopping cart in an online store) or to record the user’s browsing activity (including clicking particular buttons, logging in, or recording which pages were visited in the past). They can also be used to remember pieces of information that the user previously entered into form fields, such as names, addresses, passwords, and payment card numbers.

Cookies perform essential functions in the modern web. Perhaps most importantly, authentication cookies are the most common method used by web servers to know whether the user is logged in or not, and which account they are logged in with. Without such a mechanism, the site would not know whether to send a page containing sensitive information, or require the user to authenticate themselves by logging in. The security of an authentication cookie generally depends on the security of the issuing website and the user’s web browser, and on whether the cookie data is encrypted. Security vulnerabilities may allow a cookie’s data to be read by a hacker, used to gain access to user data, or used to gain access (with the user’s credentials) to the website to which the cookie belongs.

Tracking cookies, and especially third-party tracking cookies, are commonly used as ways to compile long-term records of individuals’ browsing histories.

If you are using Google Chrome, you can choose to delete existing cookies, allow or block all cookies, and set preferences for certain websites. Following this link:

https://support.google.com/chrome/answer/95647?co=GENIE.Platform%3DDesktop&hl=en