HTTP cookie
HTTP cookies (also called web cookies, Internet cookies, browser cookies, or simply cookies) are small blocks of data created by a web server while a user is browsing a website and placed on the user's computer or other device by the user’s web browser. Cookies are placed on the device used to access a website, and more than one cookie may be placed on a user’s device during a session.

Cookies serve useful and sometimes essential functions on the web. They enable web servers to store stateful information (such as items added in the shopping cart in an online store) on the user’s device or to track 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 save for subsequent use information that the user previously entered into form fields, such as names, addresses, passwords, and payment card numbers.

Authentication cookies are commonly used by web servers to authenticate that a user is logged in, and with which account they are logged in. Without the cookie, users would need to authenticate themselves by logging in on each page containing sensitive information that they wish to access. 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 an attacker, 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 (see cross-site scripting and cross-site request forgery for examples).

Tracking cookies, and especially third-party tracking cookies, are commonly used as ways to compile long-term records of individuals' browsing histories a potential privacy concern that prompted European and U.S. lawmakers to take action in 2011. European law requires that all websites targeting European Union member states gain "informed consent" from users before storing non-essential cookies on their device.
Q494756
data
Concept
Q11288
web server
Concept
Q278368
user
Concept
Q516508
browsing
UNK
Q35127
website
Concept
Q6368
web browser
Concept
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web
Concept
Q599031
stateful
Concept
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online store
Concept
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logging in
Concept
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pages were visited in the past
Concept
Q287539
form field
Concept
Q161157
password
Concept
Q1042071
payment card number
UNK
Q212108
authenticate
Concept
Q55603125
account
UNK
None
web browser
UNK
Q141090
encrypted
Concept
Q631425
Security vulnerabilities
Concept
Q2798820
attacker
PER
Q3702971
user data
Concept
Q371199
cross-site scripting
Concept
Q15401472
cross-site request forgery
Concept
None
third-party tracking cookies
UNK
Q2994688
browsing histories
Concept
None
privacy concern
UNK
Q458
European Union
ORG
Q764527
informed consent
Concept
Q178995
HTTP cookie
Concept
2011-01-01T00:00:00Z^^http://www.w3.org/2001/XMLSchema#dateTime
2011
DATE
subclass of
subclass of