Provided by: tcllib_1.14-dfsg-1_all bug

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 algorithm 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 strengthened 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 algorithm. 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 available then these will be used. Finally the package will  revert
       to a pure-Tcl implementation.  The programming interface remains the same, however.

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

       ::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  completes  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-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]    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/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, 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>