OTP Extended Responses (RFC2243)
Original Publication Date: 1997-Nov-01
Included in the Prior Art Database: 2019-Feb-15
Internet Society Requests For Comment (RFCs)
This document provides a specification for a type of response to an OTP [RFC 1938] challenge that carries explicit indication of the response's encoding. This document also provides a specification for a response that allows an OTP generator to request that a server re-initialize a sequence and change parameters such as the secret pass phrase. [STANDARDS-TRACK]
Network Working Group C. Metz Request for Comments: 2243 The Inner Net Category: Standards Track November 1997
OTP Extended Responses
Status of this Memo
This document specifies an Internet standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Distribution of this memo is unlimited.
Copyright (C) The Internet Society (1997). All Rights Reserved.
This document provides a specification for a type of response to an OTP [RFC 1938] challenge that carries explicit indication of the response’s encoding. Codings for the two mandatory OTP data formats using this new type of response are presented.
This document also provides a specification for a response that allows an OTP generator to request that a server re-initialize a sequence and change parameters such as the secret pass phrase.
1. Conventions, Terms, and Notation
This document specifies the data formats and software behaviors needed to use OTP extended responses. The data formats are described three ways: using an ad-hoc UNIX manual page style syntax, using augmented BNF described in sections two and three of RFC 822, and by examples. Should there be any conflict between these descriptions, the augmented BNF takes precedence. The software behaviors are described in words, and specific behavior compliance requirements are itemized using the requirements terminology (specifically, the words MUST, SHOULD, and MAY) defined in RFC 2119.
Metz Standards Track [Page 1]
RFC 2243 OTP Extended Responses November 1997
2. Extended Challenges and Extended Responses
This document builds on the protocol and terminology specified in RFC 1938 and assumes that you have already read this document and understand its contents.
An extended challenge is a single line of printable text terminated by either a new line sequence appropriate for the context of its use (e.g., ASCII CR followed by ASCII LF) or a whitespace character. It contains a standard OTP challenge, a whitespace character, and a list that generators use to determine which extended responses are supported by a server.
An extended response is a single line of printable text terminated by a new line sequence appropriate for the context of its use. It contains two or more tokens that are separated with a single colon (’:’) character. The first token contains a type specifier that indicates the format of the rest of the response. The tokens that follow are argument data for the OTP extended response. At least one token of data MUST be present.
In UNIX manual page like syntax, the general form of an extended challenge could be described as:
<standard OTP challenge> ext[,<extension set id>[, ...]]
And the general form of an extended response could be described as:
In augmented BNF...