A system and method for authenticating an HTTP message. A relying party may respond to a request from a requester by sending an HTTP message with authentication specifications to the requester. The requester responds with a new request that adheres to a scheme specified by the relying party. A framework allows for a security token to be located in an HTTP header or a message body, with various options such as fragmenting the token available. An option allows for cryptographically binding the security token to the body of a message. An authentication framework provides for an implementation by an HTTP stack or by an application.