ripemd160(n)            RIPEMD Message-Digest Algorithm           ripemd160(n)



______________________________________________________________________________

NAME
       ripemd160 - RIPEMD-160 Message-Digest Algorithm

SYNOPSIS
       package require Tcl  8.2

       package require ripemd160  ?1.0.3?

       ::ripemd::ripemd160 ?-hex? [ -channel channel | -file filename | string
       ]

       ::ripemd::hmac160 ?-hex? -key key [ -channel channel | -file filename |
       string ]

       ::ripemd::RIPEMD160Init

       ::ripemd::RIPEMD160Update token data

       ::ripemd::RIPEMD160Final token

       ::ripemd::RIPEHMAC160Init key

       ::ripemd::RIPEHMAC160Update token data

       ::ripemd::RIPEHMAC160Final token

_________________________________________________________________

DESCRIPTION
       This package is an implementation in Tcl of the RIPEMD-160 message-
       digest algorithm (1). This algorithm takes an arbitrary quantity of
       data and generates a 160-bit message digest from the input. The
       RIPEMD-160 algorithm is based upon the MD4 algorithm (2, 4) but has
       been cryptographically strengthened against weaknesses that have been
       found in MD4 (4).

       This package will use cryptkit or Trf to accelerate the digest
       computation if either package is available. In the absence of an
       accelerator package the pure-Tcl implementation will be used.

COMMANDS
       ::ripemd::ripemd160 ?-hex? [ -channel channel | -file filename | string
       ]
              Calculate the RIPEMD-160 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 ripemd160 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.

       ::ripemd::hmac160 ?-hex? -key key [ -channel channel | -file filename |
       string ]
              Calculate an Hashed Message Authentication digest (HMAC) using
              the RIPEMD-160 digest algorithm. HMACs are described in RFC 2104
              (5) and provide a RIPEMD-160 digest that includes a key. All
              options other than -key are as for the ::ripemd::ripemd160
              command.

PROGRAMMING INTERFACE
       For the programmer, hash functions can be viewed as a bucket into which
       one pours data. When you have finished, you extract a value that is
       uniquely derived from the data that was poured into the bucket. The
       programming interface to the hash operates on a token (equivalent to
       the bucket). You call RIPEMD160Init to obtain a token and then call
       RIPEMD160Update as many times as required to add data to the hash. To
       release any resources and obtain the hash value, you then call
       RIPEMD160Final. An equivalent set of functions gives you a keyed digest
       (HMAC).

       ::ripemd::RIPEMD160Init
              Begins a new RIPEMD-160 hash. Returns a token ID that must be
              used for the remaining functions.

       ::ripemd::RIPEMD160Update token data
              Add data to the hash identified by token. Calling
              RIPEMD160Update $token "abcd" is equivalent to calling
              RIPEMD160Update $token "ab" followed by RIPEMD160Update $token
              "cb". See EXAMPLES.

       ::ripemd::RIPEMD160Final 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 160
              bit RIPEMD-160 digest value.

       ::ripemd::RIPEHMAC160Init key
              This is equivalent to the ::ripemd::RIPEMD160Init command except
              that it requires the key that will be included in the HMAC.

       ::ripemd::RIPEHMAC160Update token data

       ::ripemd::RIPEHMAC160Final token
              These commands are identical to the RIPEMD160 equivalent
              commands.

EXAMPLES
              % ripemd::ripemd160 -hex "Tcl does RIPEMD-160"
              0829dea75a1a7074c702896723fe37763481a0a7



              % ripemd::hmac160 -hex -key Sekret "Tcl does RIPEMD-160"
              bf0c927231733686731dddb470b64a9c23f7f53b



              % set tok [ripemd::RIPEMD160Init]
              ::ripemd::1
              % ripemd::RIPEMD160Update $tok "Tcl "
              % ripemd::RIPEMD160Update $tok "does "
              % ripemd::RIPEMD160Update $tok "RIPEMD-160"
              % ripemd::Hex [ripemd::RIPEMD160Final $tok]
              0829dea75a1a7074c702896723fe37763481a0a7


REFERENCES
       [1]    H. Dobbertin, A. Bosselaers, B. Preneel, "RIPEMD-160, a
              strengthened version of RIPEMD"
              http://www.esat.kuleuven.ac.be/~cosicart/pdf/AB-9601/AB-9601.pdf

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

       [3]    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.

       [4]    Dobbertin, H., "Cryptanalysis of MD4", Journal of Cryptology vol
              11 (4), pp. 253-271 (1998)

       [5]    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 ripemd 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.

SEE ALSO
       md4, md5, ripemd128, sha1

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

CATEGORY
       Hashes, checksums, and encryption

COPYRIGHT
       Copyright (c) 2004, Pat Thoyts <patthoyts@users.sourceforge.net>




ripemd                               1.0.3                        ripemd160(n)
