1. RFC 8771
Independent Submission                                      A. Mayrhofer
Request for Comments: 8771                                   nic.at GmbH
Category: Experimental                                          J. Hague
ISSN: 2070-1721                                                  Sinodun
                                                            1 April 2020

The Internationalized Deliberately Unreadable Network NOtation (I-DUNNO)


   Domain Names were designed for humans, IP addresses were not.  But
   more than 30 years after the introduction of the DNS, a minority of
   mankind persists in invading the realm of machine-to-machine
   communication by reading, writing, misspelling, memorizing,
   permuting, and confusing IP addresses.  This memo describes the
   Internationalized Deliberately Unreadable Network NOtation
   ("I-DUNNO"), a notation designed to replace current textual
   representations of IP addresses with something that is not only more
   concise but will also discourage this small, but obviously important,
   subset of human activity.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for examination, experimental implementation, and

   This document defines an Experimental Protocol for the Internet
   community.  This is a contribution to the RFC Series, independently
   of any other RFC stream.  The RFC Editor has chosen to publish this
   document at its discretion and makes no statement about its value for
   implementation or deployment.  Documents approved for publication by
   the RFC Editor are not candidates for any level of Internet Standard;
   see Section 2 of RFC 7841.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at

Copyright Notice

   Copyright (c) 2020 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
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   publication of this document.  Please review these documents
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Table of Contents

   1.  Introduction
   2.  Terminology
   3.  The Notation
     3.1.  Forming I-DUNNO
     3.2.  Deforming I-DUNNO
   4.  I-DUNNO Confusion Level Requirements
     4.1.  Minimum Confusion Level
     4.2.  Satisfactory Confusion Level
     4.3.  Delightful Confusion Level
   5.  Example
   6.  IANA Considerations
   7.  Security Considerations
   8.  References
     8.1.  Normative References
     8.2.  Informative References
   Authors' Addresses

1.  Introduction

   In Section 2.3 of [RFC0791], the original designers of the Internet
   Protocol carefully defined names and addresses as separate
   quantities.  While they did not explicitly reserve names for human
   consumption and addresses for machine use, they did consider the
   matter indirectly in their philosophical communal statement: "A name
   indicates what we seek."  This clearly indicates that names rather
   than addresses should be of concern to humans.

   The specification of domain names in [RFC1034], and indeed the
   continuing enormous effort put into the Domain Name System,
   reinforces the view that humans should use names and leave worrying
   about addresses to the machines.  RFC 1034 mentions "users" several
   times, and even includes the word "humans", even though it is
   positioned slightly unfortunately, though perfectly understandably,
   in a context of "annoying" and "can wreak havoc" (see Section 5.2.3
   of [RFC1034]).  Nevertheless, this is another clear indication that
   domain names are made for human use, while IP addresses are for
   machine use.

   Given this, and a long error-strewn history of human attempts to
   utilize addresses directly, it is obviously desirable that humans
   should not meddle with IP addresses.  For that reason, it appears
   quite logical that a human-readable (textual) representation of IP
   addresses was just very vaguely specified in Section 2.1 of
   [RFC1123].  Subsequently, a directed effort to further discourage
   human use by making IP addresses more confusing was introduced in
   [RFC1883] (which was obsoleted by [RFC8200]), and additional options
   for human puzzlement were offered in Section 2.2 of [RFC4291].  These
   noble early attempts to hamper efforts by humans to read, understand,
   or even spell IP addressing schemes were unfortunately severely
   compromised in [RFC5952].

   In order to prevent further damage from human meddling with IP
   addresses, there is a clear urgent need for an address notation that
   replaces these "Legacy Notations", and efficiently discourages humans
   from reading, modifying, or otherwise manipulating IP addresses.
   Research in this area long ago recognized the potential in
   ab^H^Hperusing the intricacies, inaccuracies, and chaotic disorder of
   what humans are pleased to call a "Cultural Technique" (also known as
   "Script"), and with a certain inexorable inevitability has focused of
   late on the admirable confusion (and thus discouragement) potential
   of [UNICODE] as an address notation.  In Section 4, we introduce a
   framework of Confusion Levels as an aid to the evaluation of the
   effectiveness of any Unicode-based scheme in producing notation in a
   form designed to be resistant to ready comprehension or, heaven
   forfend, mutation of the address, and so effecting the desired
   confusion and discouragement.

   The authors welcome [RFC8369] as a major step in the right direction.
   However, we have some reservations about the scheme proposed therein:

   *  Our analysis of the proposed scheme indicates that, while
      impressively concise, it fails to attain more than at best a
      Minimum Confusion Level in our classification.

   *  Humans, especially younger ones, are becoming skilled at handling
      emoji.  Over time, this will negatively impact the discouragement

   *  The proposed scheme is specific to IPv6; if a solution to this
      problem is to be in any way timely, it must, as a matter of the
      highest priority, address IPv4.  After all, even taking the
      regrettable effects of RFC 5952 into account, IPv6 does at least
      remain inherently significantly more confusing and discouraging
      than IPv4.

   This document therefore specifies an alternative Unicode-based
   notation, the Internationalized Deliberately Unreadable Network
   NOtation (I-DUNNO).  This notation addresses each of the concerns
   outlined above:

   *  I-DUNNO can generate Minimum, Satisfactory, or Delightful levels
      of confusion.

   *  As well as emoji, it takes advantage of other areas of Unicode

   *  It can be used with IPv4 and IPv6 addresses.

   We concede that I-DUNNO notation is markedly less concise than that
   of RFC 8369.  However, by permitting multiple code points in the
   representation of a single address, I-DUNNO opens up the full
   spectrum of Unicode-adjacent code point interaction.  This is a
   significant factor in allowing I-DUNNO to achieve higher levels of
   confusion.  I-DUNNO also requires no change to the current size of
   Unicode code points, and so its chances of adoption and
   implementation are (slightly) higher.

   Note that the use of I-DUNNO in the reverse DNS system is currently
   out of scope.  The occasional human-induced absence of the magical
   one-character sequence U+002E is believed to cause sufficient
   disorder there.

   Media Access Control (MAC) addresses are totally out of the question.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "OPTIONAL" in this document are to be interpreted as described in
   BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   Additional terminology from [RFC6919] MIGHT apply.

3.  The Notation

   I-DUNNO leverages UTF-8 [RFC3629] to obfuscate IP addresses for
   humans.  UTF-8 uses sequences between 1 and 4 octets to represent
   code points as follows:

      | Char. number range    | UTF-8 octet sequence                |
      | (hexadecimal)         | (binary)                            |
      | 0000 0000 - 0000 007F | 0xxxxxxx                            |
      | 0000 0080 - 0000 07FF | 110xxxxx 10xxxxxx                   |
      | 0000 0800 - 0000 FFFF | 1110xxxx 10xxxxxx 10xxxxxx          |
      | 0001 0000 - 0010 FFFF | 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx |

                                  Table 1

   I-DUNNO uses that structure to convey addressing information as

3.1.  Forming I-DUNNO

   In order to form an I-DUNNO based on the Legacy Notation of an IP
   address, the following steps are performed:

   1.  The octets of the IP address are written as a bitstring in
       network byte order.

   2.  Working from left to right, the bitstring (32 bits for IPv4; 128
       bits for IPv6) is used to generate a list of valid UTF-8 octet
       sequences.  To allocate a single UTF-8 sequence:

       a.  Choose whether to generate a UTF-8 sequence of 1, 2, 3, or 4
           octets.  The choice OUGHT TO be guided by the requirement to
           generate a satisfactory Minimum Confusion Level (Section 4.1)
           (not to be confused with the minimum Satisfactory Confusion
           Level (Section 4.2)).  Refer to the character number range in
           Table 1 in order to identify which octet sequence lengths are
           valid for a given bitstring.  For example, a 2-octet UTF-8
           sequence requires the next 11 bits to have a value in the
           range 0080-07ff.

       b.  Allocate bits from the bitstring to fill the vacant positions
           'x' in the UTF-8 sequence (see Table 1) from left to right.

       c.  UTF-8 sequences of 1, 2, 3, and 4 octets require 7, 11, 16,
           and 21 bits, respectively, from the bitstring.  Since the
           number of combinations of UTF-8 sequences accommodating
           exactly 32 or 128 bits is limited, in sequences where the
           number of bits required does not exactly match the number of
           available bits, the final UTF-8 sequence MUST be padded with
           additional bits once the available address bits are
           exhausted.  The sequence may therefore require up to 20 bits
           of padding.  The content of the padding SHOULD be chosen to
           maximize the resulting Confusion Level.

   3.  Once the bits in the bitstring are exhausted, the conversion is
       complete.  The I-DUNNO representation of the address consists of
       the Unicode code points described by the list of generated UTF-8
       sequences, and it MAY now be presented to unsuspecting humans.

3.2.  Deforming I-DUNNO

   This section is intentionally omitted.  The machines will know how to
   do it, and by definition humans SHOULD NOT attempt the process.

4.  I-DUNNO Confusion Level Requirements

   A sequence of characters is considered I-DUNNO only when there's
   enough potential to confuse humans.

   Unallocated code points MUST be avoided.  While they might appear to
   have great confusion power at the moment, there's a minor chance that
   a future allocation to a useful, legible character will reduce this
   capacity significantly.  Worse, in the (unlikely, but not impossible
   -- see Section 3.1.3 of [RFC5894]) event of a code point losing its
   DISALLOWED property per IDNA2008 [RFC5894], existing I-DUNNOs could
   be rendered less than minimally confusing, with disastrous

   The following Confusion Levels are defined:

4.1.  Minimum Confusion Level

   As a minimum, a valid I-DUNNO MUST:

   *  Contain at least one UTF-8 octet sequence with a length greater
      than one octet.

   *  Contain at least one character that is DISALLOWED in IDNA2008.  No
      code point left behind!  Note that this allows machines to
      distinguish I-DUNNO from Internationalized Domain Name labels.

   I-DUNNOs on this level will at least puzzle most human users with
   knowledge of the Legacy Notation.

4.2.  Satisfactory Confusion Level

   An I-DUNNO with Satisfactory Confusion Level MUST adhere to the
   Minimum Confusion Level, and additionally contain two of the

   *  At least one non-printable character.

   *  Characters from at least two different Scripts.

   *  A character from the "Symbol" category.

   The Satisfactory Confusion Level will make many human-machine
   interfaces beep, blink, silently fail, or any combination thereof.
   This is considered sufficient to discourage most humans from
   deforming I-DUNNO.

4.3.  Delightful Confusion Level

   An I-DUNNO with Delightful Confusion Level MUST adhere to the
   Satisfactory Confusion Level, and additionally contain at least two
   of the following:

   *  Characters from scripts with different directionalities.

   *  Character classified as "Confusables".

   *  One or more emoji.

   An I-DUNNO conforming to this level will cause almost all humans to
   U+1F926, with the exception of those subscribed to the idna-update
   mailing list.

   (We have also considered a further, higher Confusion Level,
   tentatively entitled "BReak EXaminatIon or Twiddling" or "BREXIT"
   Level Confusion, but currently we have no idea how to go about
   actually implementing it.)

5.  Example

   An I-DUNNO based on the Legacy Notation IPv4 address ""
   is formed and validated as follows: First, the Legacy Notation is
   written as a string of 32 bits in network byte order:


   Since I-DUNNO requires at least one UTF-8 octet sequence with a
   length greater than one octet, we allocate bits in the following

                   seq1  |   seq2  |   seq3  |   seq4
                 1100011 | 0001100 | 1101100 | 10010100100

   This translates into the following code points:

        | Bit Seq.    | Character Number (Character Name)         |
        | 1100011     | U+0063 (LATIN SMALL LETTER C)             |
        | 0001100     | U+000C (FORM FEED (FF))                   |
        | 1101100     | U+006C (LATIN SMALL LETTER L)             |
        | 10010100100 | U+04A4 (CYRILLIC CAPITAL LIGATURE EN GHE) |

                                  Table 2

   The resulting string MUST be evaluated against the Confusion Level
   Requirements before I-DUNNO can be declared.  Given the example

   *  There is at least one UTF-8 octet sequence with a length greater
      than 1 (U+04A4) .

   *  There are two IDNA2008 DISALLOWED characters: U+000C (for good
      reason!) and U+04A4.

   *  There is one non-printable character (U+000C).

   *  There are characters from two different Scripts (Latin and

   Therefore, the example above constitutes valid I-DUNNO with a
   Satisfactory Confusion Level.  U+000C in particular has great
   potential in environments where I-DUNNOs would be sent to printers.

6.  IANA Considerations

   If this work is standardized, IANA is kindly requested to revoke all
   IPv4 and IPv6 address range allocations that do not allow for at
   least one I-DUNNO of Delightful Confusion Level.  IPv4 prefixes are
   more likely to be affected, hence this can easily be marketed as an
   effort to foster IPv6 deployment.

   Furthermore, IANA is urged to expand the Internet TLA Registry
   [RFC5513] to accommodate Seven-Letter Acronyms (SLA) for obvious
   reasons, and register 'I-DUNNO'.  For that purpose, U+002D ("-",
   HYPHEN-MINUS) SHALL be declared a Letter.

7.  Security Considerations

   I-DUNNO is not a security algorithm.  Quite the contrary -- many
   humans are known to develop a strong feeling of insecurity when
   confronted with I-DUNNO.

   In the tradition of many other RFCs, the evaluation of other security
   aspects of I-DUNNO is left as an exercise for the reader.

8.  References

8.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,

   [RFC3629]  Yergeau, F., "UTF-8, a transformation format of ISO
              10646", STD 63, RFC 3629, DOI 10.17487/RFC3629, November
              2003, <https://www.rfc-editor.org/info/rfc3629>.

   [RFC5894]  Klensin, J., "Internationalized Domain Names for
              Applications (IDNA): Background, Explanation, and
              Rationale", RFC 5894, DOI 10.17487/RFC5894, August 2010,

   [RFC6919]  Barnes, R., Kent, S., and E. Rescorla, "Further Key Words
              for Use in RFCs to Indicate Requirement Levels", RFC 6919,
              DOI 10.17487/RFC6919, April 2013,

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

8.2.  Informative References

   [RFC0791]  Postel, J., "Internet Protocol", STD 5, RFC 791,
              DOI 10.17487/RFC0791, September 1981,

   [RFC1034]  Mockapetris, P., "Domain names - concepts and facilities",
              STD 13, RFC 1034, DOI 10.17487/RFC1034, November 1987,

   [RFC1123]  Braden, R., Ed., "Requirements for Internet Hosts -
              Application and Support", STD 3, RFC 1123,
              DOI 10.17487/RFC1123, October 1989,

   [RFC1883]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", RFC 1883, DOI 10.17487/RFC1883,
              December 1995, <https://www.rfc-editor.org/info/rfc1883>.

   [RFC4291]  Hinden, R. and S. Deering, "IP Version 6 Addressing
              Architecture", RFC 4291, DOI 10.17487/RFC4291, February
              2006, <https://www.rfc-editor.org/info/rfc4291>.

   [RFC5513]  Farrel, A., "IANA Considerations for Three Letter
              Acronyms", RFC 5513, DOI 10.17487/RFC5513, April 2009,

   [RFC5952]  Kawamura, S. and M. Kawashima, "A Recommendation for IPv6
              Address Text Representation", RFC 5952,
              DOI 10.17487/RFC5952, August 2010,

   [RFC8200]  Deering, S. and R. Hinden, "Internet Protocol, Version 6
              (IPv6) Specification", STD 86, RFC 8200,
              DOI 10.17487/RFC8200, July 2017,

   [RFC8369]  Kaplan, H., "Internationalizing IPv6 Using 128-Bit
              Unicode", RFC 8369, DOI 10.17487/RFC8369, April 2018,

   [UNICODE]  The Unicode Consortium, "The Unicode Standard (Current
              Version)", 2019,

Authors' Addresses

   Alexander Mayrhofer
   nic.at GmbH

   Email: alexander.mayrhofer@nic.at
   URI:   https://i-dunno.at/

   Jim Hague

   Email: jim@sinodun.com
   URI:   https://www.sinodun.com/
  1. RFC 8771