Combining a browser cache and cookies to improve the security of token-based authentication protocols. A client stores a first portion of an authentication token as information (e.g., a cookie) in a first memory area. The client stores a second portion of the authentication token as server-inaccessible information (e.g., cached web content) in a second memory area. A server obtains the first and second portions from the client to recreate the authentication token to authenticate the client.