RFC 340 UNKNOWN TELNET · PROTOCOL · CHARACTER DATA

Proposed Telnet Changes

Why Telnet should keep data types and input hiding

On rfc-editor.org ↗
PUBLISHED
May 1972
AUTHORS
T.C. O'Sullivan
STREAM
Legacy
DOI
10.17487/RFC0340

RFC text

Original text · RFC Editor View on rfc-editor.org ↗
Network Working Group                                Tom O'Sullivan
Request for Comments:  340                           Raytheon Company
NIC          9933                                    Sudbury, Mass.
Categories:  Telnet
References:  RFC 328                                 15 May 1972


                        PROPOSED TELNET CHANGES

   The proposed change to the TELNET protocol calling for one standard
protocol and dropping the idea of minimum implementation seems
reasonable at this time.

   I suggest that both Data Types and Hide Your Input be kept for the
following reasons:

   Data Types:

The objection stating that switching out of ASCII results in an
irreversible change and loss of control can be met by requiring other
codes to provide to a return to ASCII.  Each other code may have its
own return code, however, it may not always be employed.  Other codes
are important for alphanumeric terminals that have special devices
attached.  Several potential cases can be cited:

   1.  Cal comp plotter attached to a teletype has logic permitting a
       program to turn the plotter on and off.  When operating I believe
       it uses an 8 bit code which could conflict with Telnet signals.

   2.  Numerically controlled machines, either controlled from a user
       terminal or code prepared by a HOST computer to be punched on the
       paper tape punch at a teletype way require the use of an arbitrary
       8 bit code.

   3.  Experiments controlled from alphanumeric terminal or sensor data
       collected through a cal-comp like connection may require the use
       of a full 8 bit code.

In these cases a transparent data type with a provision for a return
to ASCII mode seems desirable.

Hide Your Input:

As more and more use of data base systems in the network is
considered, the need for and importance of using access keys,
passwords, etc. grows.  The fact that it is difficult to select the
length of input to be hidden is not a persuasive argument.  Potential
solutions seem to exist, e.g. the protocol could provide for accepting
length statements from the user program, data base system, operating
system, etc. and in default of this, use a default length representing
the server system expected optimum length.



       [ This RFC was put into machine readable form for entry ]
       [ into the online RFC archives by BBN Corp. under the   ]
       [ direction of Alex McKenzie.                   12/96   ]

ISO Plain Language

On this page
PROBLEMA proposed Telnet change raised questions about whether data types and hidden input were still needed.
MECHANISMTom O'Sullivan argues that alternate data codes support attached equipment, while hidden input protects keys and passwords from being displayed.
THE AUTHOR'S POSITIONThe RFC proposes keeping both features and suggests ways to handle return to ASCII and the length of concealed input.

§1The Proposed Telnet Changes

Tom O'Sullivan responds to proposed changes to Telnet. He considers it reasonable to use one standard protocol rather than a minimum implementation, but recommends retaining Data Types and Hide Your Input.

The rest of the note gives reasons for retaining these two functions.

The author supports one standard Telnet protocol. He also argues that two features should remain available to users.

§2Support for Non-ASCII Data

Data Types would let a connection use codes other than ASCII. The author gives examples of equipment that may need arbitrary 8-bit codes: a plotter attached to a teletype, numerically controlled machines and experiments that collect sensor data.

He says each alternate code should provide a way to return to ASCII, though the return code need not be identical for every code.

Some attached devices use codes that are not ASCII. The author wants Telnet to carry those codes and provide a way to return to ASCII.

§3Hiding Access Keys and Passwords

Hide Your Input lets a program prevent typed characters from appearing on the user's screen. O'Sullivan says this is important as network database systems use access keys and passwords. He suggests that a program could specify how many characters to hide, with a default length when no length is supplied.

A user may need to type a password without showing it on the screen. The author suggests letting a program specify how many characters to hide.