Ubuntu Manpage: md4 - MD4 Message-Digest Algorithm

NAME

       md4 - MD4 Message-Digest Algorithm

SYNOPSIS

       package require Tcl  8.2

       package require md4  ?1.0.6?

       ::md4::md4 ?-hex? [ -channel channel | -file filename | string ]

       ::md4::hmac ?-hex? -key key [ -channel channel | -file filename | string ]

       ::md4::MD4Init

       ::md4::MD4Update token data

       ::md4::MD4Final token

       ::md4::HMACInit key

       ::md4::HMACUpdate token data

       ::md4::HMACFinal token

_________________________________________________________________________________________________

DESCRIPTION

       This  package is an implementation in Tcl of the MD4 message-digest algorithm as described
       in RFC 1320 (1) and (2). This algorithm takes an arbitrary quantity of data and  generates
       a  128-bit  message  digest  from  the  input. The MD4 algorithm is faster but potentially
       weaker than the related MD5 algorithm (3).

       If you have critcl and have built the tcllibc  package  then  the  implementation  of  the
       hashing  function  will  be  performed  by  compiled  code.  Alternatively  if cryptkit is
       available this will be used. If no accelerator package can  be  found  then  the  pure-tcl
       implementation is used. The programming interface remains the same in all cases.

COMMANDS

       ::md4::md4 ?-hex? [ -channel channel | -file filename | string ]
              Calculate  the MD4 digest of the data given in string. This is returned as a binary
              string by default. Giving the -hex option will return a hexadecimal encoded version
              of the digest.

              The  data  to  be  hashed  can  be specified either as a string argument to the md4
              command, or as a filename or a pre-opened channel. If  the  -filename  argument  is
              given  then the file is opened, the data read and hashed and the file is closed. If
              the -channel argument is given then data is read from the channel until the end  of
              file. The channel is not closed.

              Only one of -file, -channel or string should be given.

       ::md4::hmac ?-hex? -key key [ -channel channel | -file filename | string ]
              Calculate  an  Hashed  Message  Authentication  digest  (HMAC) using the MD4 digest
              algorithm. HMACs are described in RFC 2104 (4)  and  provide  an  MD4  digest  that
              includes a key. All options other than -key are as for the ::md4::md4 command.

PROGRAMMING INTERFACE

For the programmer, the MD4 hash can be viewed as a bucket into which one pours data. When
you have finished, you extract a value that is derived from the data that was poured into
the bucket. The programming interface to the MD4 hash operates on a token (equivalent to
the bucket). You call MD4Init to obtain a token and then call MD4Update as many times as
required to add data to the hash. To release any resources and obtain the hash value, you
then call MD4Final. An equivalent set of functions gives you a keyed digest (HMAC).

::md4::MD4Init
Begins a new MD4 hash. Returns a token ID that must be used for the remaining
functions.

::md4::MD4Update token data
Add data to the hash identified by token. Calling MD4Update $token "abcd" is
equivalent to calling MD4Update $token "ab" followed by MD4Update $token "cb". See
EXAMPLES.

::md4::MD4Final token
Returns the hash value and releases any resources held by this token. Once this
command completes the token will be invalid. The result is a binary string of 16
bytes representing the 128 bit MD4 digest value.

::md4::HMACInit key
This is equivalent to the ::md4::MD4Init command except that it requires the key
that will be included in the HMAC.

::md4::HMACUpdate token data

::md4::HMACFinal token
These commands are identical to the MD4 equivalent commands.

EXAMPLES

              % md4::md4 -hex "Tcl does MD4"
              858da9b31f57648a032230447bd15f25

              % md4::hmac -hex -key Sekret "Tcl does MD4"
              c324088e5752872689caedf2a0464758

              % set tok [md4::MD4Init]
              ::md4::1
              % md4::MD4Update $tok "Tcl "
              % md4::MD4Update $tok "does "
              % md4::MD4Update $tok "MD4"
              % md4::Hex [md4::MD4Final $tok]
              858da9b31f57648a032230447bd15f25

REFERENCES

       [1]    Rivest, R., "The  MD4  Message  Digest  Algorithm",  RFC  1320,  MIT,  April  1992.
              (http://www.rfc-editor.org/rfc/rfc1320.txt)

       [2]    Rivest, R., "The MD4 message digest algorithm", in A.J.  Menezes and S.A. Vanstone,
              editors, Advances in Cryptology - CRYPTO '90 Proceedings, pages 303-311,  Springer-
              Verlag, 1991.

       [3]    Rivest,  R.,  "The  MD5  Message-Digest  Algorithm",  RFC  1321,  MIT  and RSA Data
              Security, Inc, April 1992.  (http://www.rfc-editor.org/rfc/rfc1321.txt)

       [4]    Krawczyk, H.,  Bellare,  M.  and  Canetti,  R.  "HMAC:  Keyed-Hashing  for  Message
              Authentication",      RFC      2104,      February      1997.      (http://www.rfc-
              editor.org/rfc/rfc2104.txt)

BUGS, IDEAS, FEEDBACK

       This document, and the package it describes,  will  undoubtedly  contain  bugs  and  other
       problems.    Please   report   such   in   the   category   md4  of  the  Tcllib  Trackers
       [http://core.tcl.tk/tcllib/reportlist].  Please also report any ideas for enhancements you
       may have for either package and/or documentation.

KEYWORDS

       hashing, md4, message-digest, rfc 1320, rfc 1321, rfc 2104, security

COPYRIGHT

       Copyright (c) 2003, Pat Thoyts <patthoyts@users.sourceforge.net>