
                                  Sharesecret
                                       
   Sharesecret splits a secret into some parts, given a threshold. It can
   recalculate the secret by joining thresold parts. If somebody knows
   only threshold - 1 parts, he knows only the length of the secret.
   Nothing more.
   
   The latest version is 0.1.0. Remarks and comments to
   S.Karrmann@gmx.de [1] with subject sharesecret are welcomed.
   
Requirements

   Sharesecret uses the GNU MP (GNU Multiple Precision) library. To debug
   or extend sharesecret the GNU Nana and the AutoGen package would be
   useful, but are not required. If the secret has more than 2048 bits (=
   256 bytes) the calculations will be slow.
   
Installation

    1. unpack the archive, e.g. gzip -d < sharesecret_0.1.0.tar.gz | tar
       xzf -
    2. change into the created directory, e.g. cd sharesecret-0.1.0
    3. configure it, e.g. ./configure
    4. make it, e.g. make
    5. install it, e.g. make install
       
Plans for the future (0.2.0)

     * Use some code from GnuPG (GNU Privacy Guard) to do the
       calculations in locked memory, i.e. not swapped to disk.
     * Support iteration. You can split the parts again into subparts,
       which can be splitted again, ...
     * Use GNU DejaGnu to do some test.
     * Extend the use of GNU Nana.
     * Prepare RPM and SRPM.
       
Legal matters

   Sharesecret is free software; you can redistribute it and/or modify it
   under the terms of the GNU General Public License as published by the
   Free Software Foundation; either version 2 of the License, or (at your
   option) any later version.
   
   Sharesecret is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
   General Public License for more details.
   
   I don't know if it is allowed to export sharesecret from the US. The
   addresses given below points to a computer in Germany, which don't
   have such an export restriction. (And the files have been put there in
   a legal way.)
   
Bibliography

   The algorithm is described in Bruce Schneier Angewandte Kryptographie
   (Applied Cryptography) Chapter 23.2 (page 602 ff) and Chapter 3.7.
   
Download

   Sharesecret is prepared for download in different formats.
   
   Gzipped tar
          at ftp.mathematik.uni-ulm.de
          pub/soft/crypto/sharesecret_0.1.0.tar.gz [2].
          
   RPM
          To do.
          
   SRPM
          To do.
          
   Debian binary format
          at ftp.mathematik.uni-ulm.de
          pub/soft/crypto/sharesecret_0.1.0_i386.deb [3].
          
   Debian source
          at ftp.mathematik.uni-ulm.de
          pub/soft/crypto/sharesecret_0.1.0.tar.gz [4],
          ftp.mathematik.uni-ulm.de
          pub/soft/crypto/sharesecret_0.1.0.dsc [5],
          ftp.mathematik.uni-ulm.de
          pub/soft/crypto/sharesecret_0.1.0_i386.changes [6].

          These are signed with my private gnupg key:
          
          -----BEGIN PGP PUBLIC KEY BLOCK-----
          Version: GnuPG v1.0.1 (GNU/Linux)
          Comment: For info see http://www.gnupg.org

          mQGiBDgbR48RBACzjJ5dIBWL/k2rPyc/mIQPXjQ44tUfZudvtiEWOsFP/wME7XdZ
          3+BSVqkCNDbUffemwIVnSOKnF6zGn4u76D0cr6EldTlq+kakTORuAGv+gGULoJYL
          PXC2ENd4TosArdH3GMiMLUFRoMaR+nMzUKrOiQ3mzYjlgb9GkTeAYfzb/wCg5L8h
          H1tedEoy6mJQp+SR7LoqyEsD/0eEpGL4oqo3142hTeqMKAWr8t8sJGCzP7EesqxX
          EA1IMle/8x0NAPcvZ+9GTC2K1dRIJgbLzeaqfUSzLVELXs4iX9EoUn/8CMZTNp++
          4dhMqsN0nYs5JPJf3Ez+L3zUhyt5SHUVgXwWxT1FfDHUCfmBCnJjl/nxlCP5zT5P
          fdP0BACmvI5RTOk+3lVHY8SQRH7bzEXQ/1sPYpZMiy7P0yczCdyvicQCKSyXwc9r
          mttakBQ/IzDjwlO/dKv1I93gH/bGAjjDVJvWwPrK5QPYjLmYEV9cpJ4M+XedTj0l
          UY8xNRH5LuIEPoS/DIJaIhlfNB+X8JWjGYRiRwY0iix9geqborQtU3RlZmFuIEth
          cnJtYW5uIChwcml2YXQpIDxTLkthcnJtYW5uQGdteC5uZXQ+iFsEExECABsFAjgb
          R48FCQlmAYADCwoDAxUDAgMWAgECF4AACgkQTrugI6Gs6e8adgCgn8+6JIsqBkFy
          E2rExPpGB5nJdnYAnR6+vB/3oY13fsHglJfH3I53MdPruQINBDgbScsQCACiwQ+0
          YmmecX/ikO05w+Mn0WM1Nc47v0IUkwJbTf3oRdI5ArrtAzHZLGiz4unK8W9P4M4G
          IMbTTLwnL7sIkEvhMKc/j1KWXBucmbJL6DG8rf+qDMrTs18DYAujQrRWKjjk+3ik
          sEQfnxooUOMSWTiaAHtQl+sAUpCV+v2Q46wqXUIetBibbnJpMxYnw9Hn+KCvZErG
          rQy+yaP/6zM6w+yPcuIQBbqYisI3BBqB5aiJNi3Z3ZEJAi+PImtIBdzboR3mPJjs
          +fNyE65hUE9HKaBF38hsWmryFNoPaPpm0hxnJncs3mLlGMavYZbnzGqxIoeZZMWL
          6ZTVgHxGTkJFr8wvAAQNB/wPA/Q3+LHR9HtPnw6roPtpTpM8bmbOCQbcka39gp21
          iKEcjikR+BKpoCK7owr6uRUcN2wpfpLLPJDkFDlp2Oo9SMphTuJR5Jx5+pQ7lWSp
          ysT/CcuylDmXh+56eJVxpXNlbVZiN2ifnzIApT77Wh/8CDvsiNu6jJNJKNmJ8t/d
          kpKFpm/GuDxkgZFR4zf9HrfGhqPuSvHWmlbJirozxHI+Ua+l79cwqahlQlcqX5Ml
          MOj6ttimEf7ZvTzAt8FcwPkuxPR640PZz2bWO9iYjz2k/GJuAMkQoSId1C4WWkuU
          yrsg9wE/vVKTcIbEafcsRXoAudoY6Ykfy/3i9ESgv2joiEwEGBECAAwFAjgbScsF
          CQlmAYAACgkQTrugI6Gs6e/bMgCdGrcjfaML58aHKBtjEi4lPky7HPcAoK2y2+s1
          cERHpmQybpGa5LX/2fZ6
          =WMfU
          -----END PGP PUBLIC KEY BLOCK-----

References

   1. mailto:S.Karrmann@gmx.net?subject=sharesecret
   2. ftp://ftp.mathematik.uni-ulm.de/pub/soft/crypto/sharesecret_0.1.0.tar.gz
   3. ftp://ftp.mathematik.uni-ulm.de/pub/soft/crypto/sharesecret_0.1.0.deb
   4. ftp://ftp.mathematik.uni-ulm.de/pub/soft/crypto/sharesecret_0.1.0.tar.gz
   5. ftp://ftp.mathematik.uni-ulm.de/pub/soft/crypto/sharesecret_0.1.0.dsc
   6. ftp://ftp.mathematik.uni-ulm.de/pub/soft/crypto/sharesecret_0.1.0_i386.changes

Comments are welcome.

	- Stefan Karrmann <S.Karrmann@gmx.net>
