Ubuntu Manpage: md4 - MD4 Message-Digest Algorithm

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 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      SF      Trackers
       [http://sourceforge.net/tracker/?group_id=12883].   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>