Cookie

A cookie, in the context of web browsing, is a small piece of data sent from a website and stored on the 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 pieces of information that the user previously entered into form fields, such as names, addresses, passwords, and payment card numbers.

Cookies are essential for the modern web, offering core functionalities in user authentication, session management, and personalized user experiences. Without cookies, user experience on the web would be significantly more fragmented and less convenient, requiring users to re-enter information repeatedly. For businesses, cookies facilitate understanding user behavior, enabling targeted advertising, and analytics, which help improve website usability and content. However, this utility comes with privacy implications, as cookies can be used to track users across multiple sites, leading to concerns over how personal data is collected, used, and shared.

The operation of cookies involves a simple yet powerful mechanism. When a user visits a website, the site’s server sends a cookie to the user’s browser, which stores it for a specified period. This cookie might contain information like user preferences, session identifiers, or tracking IDs. Upon subsequent visits, the browser sends the cookie back to the server, informing it of previous activity or preferences. This back-and-forth communication enables websites to maintain state and provide tailored experiences. Cookies can be “session” cookies, which expire when the browser is closed, or “persistent” cookies, which remain until they expire or are deleted by the user.

While cookies enhance web functionality and user experience, they also raise privacy and security concerns. For example, tracking cookies can compile long-term records of individuals’ browsing histories, which is a significant privacy concern. Moreover, cookies can be exploited for malicious purposes, such as session hijacking and cross-site scripting attacks. Legislation and browser technologies now offer users greater control over cookie usage, but awareness and understanding of cookie management remain crucial. Examples of best practices include websites asking for consent before storing cookies, using secure and HttpOnly attributes to protect cookies, and users regularly clearing cookies to protect their privacy.