.ROBLOSECURITY

The .ROBLOSECURITY cookie is a browser cookie used by the ROBLOX website to store user sessions in a web browser. Its content is a hash that is used by the website to determine what user account the user agent is logged in. This means that if a user can be tricked through social engineering into revealing the content of this cookie, users who are aware of it can log into the account of the user by creating a cookie named “.ROBLOSECURITY” with the content revealed by the user. The hash used by the .ROBLOSECURITY cookie is only valid for a limited time.

Two methods of invalidating the hash are by changing your password or logging out and then in. This is helpful if you recently gave away your .ROBLOSECURITY cookie to a scammer.