Cookie

A cookie is a small piece of data sent from a website and stored on a user's computer by the user's web browser while the user is browsing. 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 arbitrary pieces of information that the user previously entered into form fields such as names, addresses, passwords, and credit card numbers.

Key Attributes

Session Cookies. These are temporary cookies that remain in the cookie file of your browser until you leave the site. They enable a site to track each of your movements from page to page so you don't get asked for the same information you've already given to the site.

Persistent Cookies. These remain in the cookie file of your browser for much longer (though how long depends on the lifetime of the specific cookie). They are used to store information between sessions, such as user preferences or login status.

Secure Cookies. These are transmitted over secure protocols (HTTPS), meaning they are encrypted for security. They are used to ensure that the data in the cookie is transmitted securely between the web server and browser.

HttpOnly Cookies. These cannot be accessed through client-side scripts; this setting helps mitigate the risk of client-side script accessing the protected cookie (if the browser supports it).

SameSite Cookies. This attribute can be used to prevent cookies from being sent in cross-site requests, helping to mitigate CSRF (Cross Site Request Forgery) attacks.

Functionality

Session Management. Cookies are essential for managing user sessions for web applications. They help servers to remember users' states across page requests.

Personalization. Websites use cookies to remember information about users in order to tailor the experience according to their preferences.

Tracking. Cookies can track user behavior, which is valuable for analytics and targeted advertising.

Cookies play a critical role in enhancing user experience and providing essential functionalities in web applications, but they also raise concerns about privacy and the security of the information they store.