Network Working Group N. Shanks Internet-Draft November 30, 2012 Intended status: Standards Track Expires: June 3, 2013 Hypertext Transfer Protocol (HTTP) Form Authentication Scheme draft-shanks-http-form-authentication-01 Abstract This document defines the "Form" HTTP authentication scheme. It allows web developers access to standard HTTP-based authentication mechanisms whilst retaining control over the look and feel of their log-in page, without requiring any client-side scripting. Comments are requested and should be addressed to the author. Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on June 3, 2013. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Shanks Expires June 3, 2013 [Page 1] Internet-Draft HTTP Form Authentication November 2012 1. Introduction This scheme builds upon the Digest authentication scheme defined by [RFC2617] and updated by [draft-ietf-httpbis-p7-auth], but changes the process for creating the A1 value (section 3.2.2.2 of RFC 2617), and specifies different user agent behaviour. It is intended to allow migration away from application/x-www-form-urlencoded requests over unencrypted HTTP which transmit the password in clear-text, a common occurance on the web (for example see Look At All Of These Passwords! [1]); and to do so in a way that, when widely supported by user agents and server software, will also allow simple migration from Digest authentication, should developers who are already using that scheme wish to take control of their credentials solicitation appearance. It is intended to function independent of Transport Layer Security (TLS) [RFC5246], serving only to obscure passwords from eavesdroppers, however nothing prevents its use over an encrypted connection if so desired. 1.1. Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. The terms "form field", "form input" and "form output" are used somewhat interchangably and refer to elements generated by markup which may be submitted with the form by the user agent. The phrase "submittable field" means any form field which would generate a key-value pair on form submission. In HTML 4 that would mean every input type except an unchecked checkbox and a radio group with no selected element. A form field's "name" refers to the property of the field which is used to create the key in each key-value pair submitted by the form. In HTML this would be the value of the name attribute of e.g. an input element. The phrase "reserved name pattern" indicates a form field name which begins and ends with an underscore character "_", ASCII value decimal 95. As a regular expression, this would be represented by the pattern /_.*_/ The "effective checksum algorithm" is determined as described by section 3.2.1 of RFC 2617, under "algorithm". The string obtained by applying the checksum algorithm to the data "data" will be denoted H(data). The notation unq(X) means the value Shanks Expires June 3, 2013 [Page 2] Internet-Draft HTTP Form Authentication November 2012 of the quoted-string X without the surrounding quotes. Shanks Expires June 3, 2013 [Page 3] Internet-Draft HTTP Form Authentication November 2012 2. The "Form" Authentication Scheme Supporting user agents MUST present to the user (or to another software/hardware agent acting on behalf of the user) the parsed body of a response which uses either a HTTP status code of 401 and a WWW- Authenticate header specifying the "Form" scheme; or a 407 status code and a Proxy-Authenticate header specifying the "Form" scheme. This response body MUST contain a form in a format that the user agent can understand, e.g. HTML