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ripemd128(n)                           RIPEMD Message-Digest Algorithm                          ripemd128(n)



____________________________________________________________________________________________________________

NAME
       ripemd128 - RIPEMD-128 Message-Digest Algorithm

SYNOPSIS
       package require Tcl  8.2

       package require ripemd128  ?1.0.3?

       ::ripemd::ripemd128 ?-hex? [ -channel channel | -file filename | string ]

       ::ripemd::hmac128 ?-hex? -key key [ -channel channel | -file filename | string ]

       ::ripemd::RIPEMD128Init

       ::ripemd::RIPEMD128Update token data

       ::ripemd::RIPEMD128Final token

       ::ripemd::RIPEHMAC128Init key

       ::ripemd::RIPEHMAC128Update token data

       ::ripemd::RIPEHMAC128Final token

____________________________________________________________________________________________________________

DESCRIPTION
       This  package  is an implementation in Tcl of the RIPEMD-128 message-digest algorithm (1). This algo-rithm algorithm
       rithm takes an arbitrary quantity of data and generates a 128-bit message digest from the input.  The
       RIPEMD-128  algorithm is based upon the MD4 algorithm (2, 4) but has been cryptographically strength-ened strengthened
       ened against weaknesses that have been found in MD4 (4). RIPEMD-128 has been designed to be a drop-in
       replacement  for  MD4  and  MD5  (5). If security is the major consideration, then RIPEMD-160 or SHA1
       should be considered.

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

COMMANDS
       ::ripemd::ripemd128 ?-hex? [ -channel channel | -file filename | string ]
              Calculate  the  RIPEMD-128  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 ripemd128 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::hmac128 ?-hex? -key key [ -channel channel | -file filename | string ]
              Calculate an Hashed Message Authentication digest (HMAC) using  the  RIPEMD-128  digest  algo-rithm. algorithm.
              rithm.  HMACs  are  described  in RFC 2104 (6) and provide a RIPEMD-128 digest that includes a
              key. All options other than -key are as for the ::ripemd::ripemd128 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
       RIPEMD128Init  to  obtain a token and then call RIPEMD128Update as many times as required to add data
       to the hash. To release any resources and obtain the hash value, you  then  call  RIPEMD128Final.  An
       equivalent set of functions gives you a keyed digest (HMAC).

       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 both the Trf and Memchan extensions  are  avail-able available
       able then these will be used. Finally the package will revert to a pure-Tcl implementation.  The pro-gramming programming
       gramming interface remains the same, however.

       ::ripemd::RIPEMD128Init
              Begins a new RIPEMD-128 hash. Returns a token ID that must be used  for  the  remaining  func-tions. functions.
              tions.

       ::ripemd::RIPEMD128Update token data
              Add  data to the hash identified by token. Calling RIPEMD128Update $token "abcd" is equivalent
              to calling RIPEMD128Update $token "ab" followed by RIPEMD128Update $token "cb". See  EXAMPLES.

       ::ripemd::RIPEMD128Final 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 RIPEMD-128 digest value.

       ::ripemd::RIPEHMAC128Init key
              This is equivalent to the ::ripemd::RIPEMD128Init command except that it requires the key that
              will be included in the HMAC.

       ::ripemd::RIPEHMAC128Update token data

       ::ripemd::RIPEHMAC128Final token
              These commands are identical to the RIPEMD128 equivalent commands.


EXAMPLES
       % ripemd::ripemd128 -hex "Tcl does RIPEMD-128"
       3cab177bae65205d81e7978f63556c63


       % ripemd::hmac128 -hex -key Sekret "Tcl does RIPEMD-128"
       b359dc5971a05beea0be7b106b30e389


       % set tok [ripemd::RIPEMD128Init]
       ::ripemd::1
       % ripemd::RIPEMD128Update $tok "Tcl "
       % ripemd::RIPEMD128Update $tok "does "
       % ripemd::RIPEMD128Update $tok "RIPEMD-128"
       % ripemd::Hex [ripemd::RIPEMD128Final $tok]
       3cab177bae65205d81e7978f63556c63


REFERENCES
       [1]    H. Dobbertin, A. Bosselaers, B.  Preneel,  "RIPEMD-160,  a  strengthened  version  of  RIPEMD"
              http://www.esat.kuleuven.ac.be/~cosicart/pdf/AB-96_1/AB-96_1.pdf

       [2]    Rivest,  R.,  "The  MD4 Message Digest Algorithm", RFC 1320, MIT, April 1992. (http://www .rfc-
              editor.org/rfc/rfc132_.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]    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)

       [6]    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  ripemd   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
       md4, md5, ripemd160, 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                                       ripemd128(n)