md4--3tcl

md4(n)                                md4                               md4(n)



______________________________________________________________________________

NAME
       md4 - MD4 Message-Digest Algorithm

SYNOPSIS
       package require Tcl  8.2

       package require md4  ?1.0.2?

       ::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).

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  argu-
              ment  to the md4 command, or as a filename or a pre-opened chan-
              nel. 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 equiva-
       lent set of functions gives you a keyed digest (HMAC).

       If  you  have critcl and have built the tcllibc package then the imple-
       mentation of the hashing function will be performed by compiled code  -
       otherwise  there  is  a  pure-tcl equivalent. The programming interface
       remains the same, however.

       ::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-edi-
              tor.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)

SEE ALSO
       md5, sha1

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

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



md4                                  1.0.2                              md4(n)