Flash Cookies

Data storage files created by Adobe Flash Player that function similarly to browser cookies but with different characteristics and controls. Flash cookies (also called Local Shared Objects or LSOs) can store significantly more data than regular cookies, persist across browsers on the same device, and historically weren't controlled by browser cookie settings, making them difficult for users to manage. Flash cookies were sometimes used to respawn deleted regular cookies, a practice called 'cookie resurrection' that regulators viewed as deceptive. With Adobe ending Flash Player support in 2020, Flash cookies are largely obsolete. However, they remain relevant in privacy discussions as an example of tracking technologies that circumvent user controls. The Flash cookie experience influenced privacy regulations emphasizing that all tracking technologies—not just HTTP cookies—require transparency and appropriate consent. Modern privacy laws cover all similar tracking technologies to prevent circumvention of cookie controls.