Cookies, as implemented in current web technologies, fundamentally store a randomly generated unique identifier, which is then linked to the user's browser during interactions with specific websites. These identifiers do not inherently contain personal data; however, the association of a consistent identifier with persistent web activity enables the aggregation of detailed behavioral profiles over time. Evidence demonstrates the following key findings:
- Unique identifiers in cookies facilitate cross-session tracking: Once assigned, a cookie's identifier enables the recognition of returning browsers, allowing sites to correlate multiple visits and actions to a single profile (Mayer & Mitchell, 2012).
- Personal identification becomes possible through profile enrichment: Although cookies themselves do not store names or direct identifiers, when linked with user-provided data (e.g., via logins, form submissions), the cookie can become a proxy for personal identity. This linkage is especially prevalent on platforms requiring authentication (Krishnamurthy & Wills, 2009).
- Third-party cookies amplify privacy concerns: Third-party tracking mechanisms, set by entities other than the website being visited, aggregate browsing data across domains. This data enables potentially invasive profiling and re-identification, even without explicit user consent (Englehardt & Narayanan, 2016).
- Regulatory frameworks consider cookies as personal data: Under GDPR and CCPA, cookies—especially those enabling user profiling or targeted advertising—are treated as personal data. Explicit consent is mandated before storing or accessing such identifiers (“Regulation (EU) 2016/679,” 2016).
- Empirical studies confirm identification risks: Research has confirmed that combining cookie data with auxiliary information from account registrations or third-party brokers can yield high-confidence user identification rates (Acar et al., 2014).
In summary, while a raw cookie value is not an explicit identifier, persistent identifiers combined with behavioral and volunteered information can lead to de facto personal identification. This risk is heightened by the aggregation of third-party data and the lack of user awareness or control.
