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md4(n)                                  MD4 Message-Digest Algorithm                                  md4(n)



____________________________________________________________________________________________________________

NAME
       md4 - MD4 Message-Digest Algorithm

SYNOPSIS
       package require Tcl  8.2

       package require md4  ?1.0?

       ::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 algo-rithm algorithm
       rithm (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 pro-gramming programming
       gramming  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 func-tions functions
       tions 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 com-pletes completes
              pletes 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/rfc132_.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/rfc21_4.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  SF  Trackers  [http://source -
       forge.net/tracker/? group_id=12883].  Please also report any ideas for enhancements you may  have  for
       either package and/or documentation.

SEE ALSO
       md5, sha1

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

CATEGORY
       Hashes, checksums, and encryption

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




md4                                                 1.0.5                                             md4(n)