Libgcrypt - The GNU Crypto Library
		   ------------------------------------
                            Version 1.4.6
 

    Copyright 2000, 2002, 2003, 2004, 2007, 2008,
              2009, 2010 Free Software Foundation, Inc.

    This file is free software; as a special exception the author gives
    unlimited permission to copy and/or distribute it, with or without
    modifications, as long as this notice is preserved.

    This file is distributed in the hope that it will be useful, but
    WITHOUT ANY WARRANTY, to the extent permitted by law; without even the
    implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.



    Overview
    --------

    Libgcrypt is a general purpose crypto library based on the code
    used in GnuPG.  Libgcrypt depends on the library `libgpg-error',
    which must be installed correctly before Libgcrypt is to be built.
    Libgcrypt is distributed under the LGPL, see the section "License"
    below for details.


    Build Instructions
    ------------------

    The download canonical location for libgcrypt is:

      ftp://ftp.gnupg.org/gcrypt/libgcrypt/
     
    To build libgcrypt you need libgpg-error:

      ftp://ftp.gnupg.org/gcrypt/libgpg-error/

    You should get the latest versions of course.

    After building and installing the libgpg-error package, you may
    continue with Libgcrypt installation As with allmost all GNU
    packages, you just have to do

       ./configure
       make
       make check
       make install

    The "make check" is not required but a good idea to see whether
    the library works as expected.  The check takes some while and
    prints some benchmarking results.  Before doing "make install" you
    probably need to become root.

    To build libgcrypt for Microsoft Windows, you need to have the
    mingw32 cross-building toolchain installed.  Instead of running a
    plain configure you use

      ./autogen.sh --build-w32
      make
      make install
      
    By default this command sequences expectsd a libgpg-error
    installed below $HOME/w32root and installs libgcrypt to that
    directory too.  See the autogen.sh code for details.

    The documentation is available as an Info file (gcrypt.info).  To
    build documentation in PDF, run this:

      cd doc
      make pdf



    Mailing List
    ------------

    You may want to join the developer's mailing list
    [email protected] by sending mail with a subject of
    "subscribe" to [email protected].  An archive of this
    list is available at http://lists.gnupg.org .


    Configure options 
    -----------------
    Here is a list of configure options which are sometimes useful 
    for installation.

     --enable-m-guard
                     Enable the integrated malloc checking code. Please
                     note that this feature does not work on all CPUs
                     (e.g. SunOS 5.7 on UltraSparc-2) and might give
                     you a bus error.

     --disable-asm
                     Do not use assembler modules.  It is not possible 
                     to use this on some CPU types.
                    
     --enable-ld-version-script
                     Libgcrypt tries to build a library where internal
                     symbols are not exported.  This requires support
                     from ld and is currently enabled for a few OSes.
                     If you know that your ld supports the so called
                     ELF version scripts, you can use this option to
                     force its use.  OTOH, if you get error message
                     from the linker, you probably want to use this
                     option to disable the use of version scripts.
                     Note, that you should never ever use an
                     undocumented symbol or one which is prefixed with
                     an underscore. 

     --enable-ciphers=list
     --enable-pubkey-ciphers=list
     --enable-digests=list
                     If not otherwise specified, all algorithms
                     included in the libgcrypt source tree are built.
		     An exception are algorithms, which depend on
		     features not provided by the system, like 64bit
		     data types.  With these switches it is possible
                     to select exactly those algorithm modules, which
		     should be built.  The algorithms are to be
                     separated by spaces, commas or colons.  To view
                     the list used with the current build the program
                     tests/version may be used.

     --disable-endian-check
                     Don't let configure test for the endianness but
                     try to use the OS provided macros at compile
                     time.  This is helpful to create OS X fat binaries.

     --enable-random-daemon
                     Include support for a global random dawmon and
                     build the daemon.  This is an experimental feature.

     --enable-mpi-path=EXTRA_PATH
                     Prepend EXTRA_PATH to list of CPU specific
                     optimizations.  For example, if you want to add
                     optimizations forn a Intel Pentium 4 compatible
                     CPU, you may use
                        --enable-mpi-path=pentium4/sse2:pentium4/mmx
                     Take care: The generated library may crash on
                     non-compatible CPUs.

     --enable-random=NAME 
                     Force the use of the random gathering module
		     NAME.  Default is either to use /dev/random or
		     the auto mode.  Possible values for NAME are:
		       egd - Use the module which accesses the
			     Entropy Gathering Daemon. See the webpages
			     for more information about it.
		      unix - Use the standard Unix module which does not
			     have a very good performance.
		     linux - Use the module which accesses /dev/random.
			     This is the first choice and the default one
			     for GNU/Linux or *BSD.
                      auto - Compile linux, egd and unix in and 
                             automagically select at runtime.
  
     --enable-hmac-binary-check
                     Include support to check the binary at runtime
                     against a HMAC checksum.  This works only in FIPS
                     mode and on systems providing the dladdr function.

     --disable-padlock-support
                     Disable support for the PadLock engine of VIA
                     processors.  The default is to use PadLock if
                     available.  Try this if you get problems with
                     assembler code.

     --disable-O-flag-munging
                     Some code is too complex for some compilers while
                     in higher optimization modes, thus the compiler
                     invocation is modified to use a lower
                     optimization level.  Usually this works very well
                     but on some platforms these rules break the
                     invocation.  This option may be used to disable
                     the feature under the assumption that either good
                     CFLAGS are given or the compiler can grok the code.
      

    Build Problems
    --------------

    We can't check all assembler files, so if you have problems
    assembling them (or the program crashes) use --disable-asm with
    ./configure.  If you opt to delete individual replacement files in
    hopes of using the remaining ones, be aware that the configure
    scripts may consider several subdirectories to get all available
    assembler files; be sure to delete the correct ones.  Never delete
    udiv-qrnnd.S in any CPU directory, because there may be no C
    substitute (in mpi/genereic).  Don't forget to delete
    "config.cache" and run "./config.status --recheck".  We got a few
    reports about problems using versions of gcc earlier than 2.96
    along with a non-GNU assembler (as).  If this applies to your
    platform, you can either upgrade gcc to a more recent version, or
    use the GNU assembler.

    Some make tools are broken - the best solution is to use GNU's
    make.  Try gmake or grab the sources from a GNU archive and
    install them.

    Specific problems on some machines:

      * IBM RS/6000 running AIX

	Due to a change in gcc (since version 2.8) the MPI stuff may
	not build. In this case try to run configure using:
	    CFLAGS="-g -O2 -mcpu=powerpc" ./configure

      * SVR4.2 (ESIX V4.2 cc)

        Due to problems with the ESIX as(1), you probably want to do:
            CFLAGS="-O -K pentium" ./configure --disable-asm

      * SunOS 4.1.4
      
         ./configure ac_cv_sys_symbol_underscore=yes

      * Sparc64 CPUs

        We have reports about failures in the AES module when
        compiling using gcc (e.g. version 4.1.2) and the option -O3;
        using -O2 solves the problem.



    License
    -------
    
    The library is distributed under the terms of the GNU Lesser
    General Public License (LGPL); see the file COPYING.LIB for the
    actual terms.  The helper programs (e.g. gcryptrnd and getrandom)
    as well as the documentation are distributed under the terms of
    the GNU General Public License (GPL); see the file COPYING for the
    actual terms.

    This library used to be available under the GPL - this was changed
    with version 1.1.7 with the rationale that there are now many free
    crypto libraries available and many of them come with capabilities
    similar to Libcrypt.  We decided that to foster the use of
    cryptography in Free Software an LGPLed library would make more
    sense because it avoids problems due to license incompatibilities
    between some Free Software licenses and the GPL.

    Please note that in many cases it is better for a library to be
    licensed under the GPL, so that it provides an advantage for free
    software projects.  The Lesser GPL is so named because it does
    less to protect the freedom of the users of the code that it
    covers.  See http://www.gnu.org/philosophy/why-not-lgpl.html for
    more explanation.


    Contact
    -------

    See the file AUTHORS.

    Commercial grade support for Libgcrypt is available; please see
    http://www.gnupg.org/service.html .


  This file is Free Software; as a special exception the authors gives
  unlimited permission to copy and/or distribute it, with or without
  modifications, as long as this notice is preserved. For conditions
  of the whole package, please see the file COPYING.  This file is
  distributed in the hope that it will be useful, but WITHOUT ANY
  WARRANTY, to the extent permitted by law; without even the implied
  warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.