This document specifies the Authentication Web Service Protocol. This protocol enables a protocol client to determine which type of authentication is used by a Web site. In addition, if authentication requests for that site are redirected to an HTML form, then this protocol enables a protocol client and a protocol server to authenticate a user.
Sections 1.8, 2, and 3 of this specification are normative and can contain the terms MAY, SHOULD, MUST, MUST NOT, and SHOULD NOT as defined in RFC 2119. Sections 1.5 and 1.9 are also normative but cannot contain those terms. All other sections and examples in this specification are informative.