One document matched: draft-josefsson-rfc4648-impl-report-00.txt

Network Working Group                                       S. Josefsson
Internet-Draft                                                    SJD AB
Intended status: Informational                              May 28, 2009
Expires: November 29, 2009


                     RFC 4648 Implementation Report
                 draft-josefsson-rfc4648-impl-report-00

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Abstract

   This is an implementation report of RFC4648, for the purpose of
   advancing the document to Draft Standard.




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   See <http://josefsson.org/base-encoding/> for more information.


Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . . . 3
   2.  Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   3.  Methodology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   4.  Exceptions  . . . . . . . . . . . . . . . . . . . . . . . . . . 3
   5.  Implementations Tested  . . . . . . . . . . . . . . . . . . . . 4
     5.1.  GNU Coreutils: base64 . . . . . . . . . . . . . . . . . . . 4
   6.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . 4
   7.  Security Considerations . . . . . . . . . . . . . . . . . . . . 4
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4
   9.  References  . . . . . . . . . . . . . . . . . . . . . . . . . . 5
     9.1.  Normative References  . . . . . . . . . . . . . . . . . . . 5
     9.2.  Informative References  . . . . . . . . . . . . . . . . . . 5
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . . . 5

































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1.  Introduction

   This is an implementation report of The Base16, Base32, and Base64
   Data Encodings [RFC4648] document.  It follows the outline suggested
   by [I-D.dusseault-impl-reports].


2.  Summary

   The "base64" encoding have a long history of being used in Internet
   protocols, the earliest use in the RFC series appears to be
   [RFC0989].  It has been widely implemented as part of MIME [RFC2045],
   which is already a Draft Standard.  The "base64url" alphabet does not
   appear to be widely deployed.

   The "base32" encoding is not as widely used as base64, but has
   applications in the case insensitive systems.  The "base32" encoding
   is used by [I-D.ietf-sasl-gs2].  The "base32hex" encoding is used by
   [RFC5155], and a restricted form is used by [RFC2938].

   The "base16" encoding is usually referred to as hexadecimal, or hex
   encoding, and is used in many protocols and informally in technical
   documents.


3.  Methodology

   We identified that we wanted to test the following encodings: base64,
   base64url, base32, base32hex, base16.

   The primary test is of course that basic encoding and decoding works
   and lead to expected results.

   Section 3 of RFC 4648 discuss some implementation discrepancies of
   base encoding.  To possibly find interoperability problems, we
   checked and documented these corner-cases separately.  In particular:
   how line feeds are handled during encoding and decoding [LF], whether
   padding is done correctly [PAD], how non-alphabetical characters are
   handled [NONALPHA], whether pad bits are zero or not [ZEROBITS].

   A useful test case whether pad bit handling is appropriate is "YR=="
   which is a non-canonical encoding of "a" (ASCII 0x61) that normally
   is encoded as "YQ==".


4.  Exceptions

   Encoding and decoding of data interoperate well.



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   Some tools accepted non-canonical encodings, but none appeared to
   ever generate them.  This is consistent with the requirements in
   section 3.5 of RFC 4648.

   We acknowledge that many implementations of base64 were written for a
   general purpose, and thus may not follow some of the guidelines
   (e.g., related to line feeds) in RFC 4648 strictly.  However we
   believe this should not be a reason against Draft Standard status
   because the document is clear on the issues and the minor variations
   does not appear to lead to any problem.


5.  Implementations Tested

5.1.  GNU Coreutils: base64

   There is a "base64" command line tool, written in C, included in GNU
   Coreutils [GNU-Coreutils-Base64].  It supports the "base64" alphabet.

   [LF]: On encoding, it wraps output after 76 characters (same as
   MIME).  On decoding, it accepts line-wrapped input.

   [PAD]: It appears to pad data properly.

   [NONALPHA]: It appears to return a non-zero error code if the input
   contains non-alphabetical characters.

   [ZEROBITS]: On encoding, the pad bits are zero.  On decoding, it
   appears to accept non-zero pad bits.


6.  Acknowledgements

   TBA


7.  Security Considerations

   See RFC 4648 for security considerations.


8.  IANA Considerations

   This document has no actions for IANA.


9.  References




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9.1.  Normative References

   [RFC4648]  Josefsson, S., "The Base16, Base32, and Base64 Data
              Encodings", RFC 4648, October 2006.

9.2.  Informative References

   [I-D.dusseault-impl-reports]
              Dusseault, L. and R. Sparks, "Guidance on Interoperation
              and Implementation Reports",
              draft-dusseault-impl-reports-02 (work in progress),
              May 2009.

   [RFC0989]  Linn, J. and IAB Privacy Task Force, "Privacy enhancement
              for Internet electronic mail: Part I: Message encipherment
              and authentication procedures", RFC 989, February 1987.

   [RFC2045]  Freed, N. and N. Borenstein, "Multipurpose Internet Mail
              Extensions (MIME) Part One: Format of Internet Message
              Bodies", RFC 2045, November 1996.

   [RFC2938]  Klyne, G. and L. Masinter, "Identifying Composite Media
              Features", RFC 2938, September 2000.

   [RFC5155]  Laurie, B., Sisson, G., Arends, R., and D. Blacka, "DNS
              Security (DNSSEC) Hashed Authenticated Denial of
              Existence", RFC 5155, March 2008.

   [I-D.ietf-sasl-gs2]
              Josefsson, S. and N. Williams, "Using GSS-API Mechanisms
              in SASL: The GS2 Mechanism Family", draft-ietf-sasl-gs2-13
              (work in progress), May 2009.

   [GNU-Coreutils-Base64]
              Josefsson, S., "GNU Coreutils "base64" tool version 7.2",
              WWW http://www.gnu.org/software/coreutils/, May 2009.


Author's Address

   Simon Josefsson
   SJD AB

   Email: simon@josefsson.org







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