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GnuTLS README -- Important introductory notes

GnuTLS implements the TLS/SSL (Transport Layer Security aka Secure Sockets Layer) protocol. GnuTLS is a GNU project. Additional information can be found at https://www.gnutls.org/.


This README is targeted for users of the library who build from sources but do not necessarily develop. If you are interested in developing and contributing to the GnuTLS project, please see README-alpha and visit https://www.gnutls.org/manual/html_node/Contributing.html.


A typical command sequence for building the library is shown below. A complete list of options available for configure can be found by running './configure --help'.

    cd gnutls-<version>
    ./configure --prefix=/usr
    make check
    sudo make install

The commands above build and install the static archive (libgnutls.a), the shared object (libgnutls.so), and additional binaries such as certtool and gnutls-cli.

The library depends on libnettle and gmplib. gmplib: for big number arithmetic, https://gmplib.org/ nettle: for cryptographic algorithms, https://www.lysator.liu.se/~nisse/nettle/

Optionally it may use the following libraries: libtasn1: For ASN.1 parsing (a copy is included, if not found), https://www.gnu.org/software/libtasn1/ p11-kit: for smart card support, https://p11-glue.github.io/p11-glue/p11-kit.html libtspi: for Trusted Platform Module (TPM) support, https://trousers.sourceforge.net/ libunbound: For DNSSEC/DANE support, https://unbound.net/ libz: For compression support, https://www.zlib.net/ libidn: For supporting internationalized DNS names (IDNA 2003), https://www.gnu.org/software/libidn/ * libidn2: For supporting internationalized DNS names (IDNA 2008), https://www.gnu.org/software/libidn/#libidn2

To configure libnettle for installation and use by GnuTLS, a typical command sequence would be:

    cd nettle-<version>
    ./configure --prefix=/usr --disable-openssl --enable-shared
    sudo make install

For the Nettle project, --enable-shared will instruct automake and friends to build and install both the static archive (libnettle.a) and the shared object (libnettle.so).

In case you are compiling for an embedded system, you can disable unneeded features of GnuTLS. In general, it is usually best not to disable anything (for future mailing list questions and possible bugs).

Depending on your installation, additional libraries, such as libtasn1 and zlib, may be required.


See the documentation in doc/ and online at https://www.gnutls.org/manual.


See the examples in doc/examples/ and online at 'How To Use GnuTLS in Applications' at https://www.gnutls.org/manual.


The project collects and publishes information on past security incidents and vulnerabilities. Open information exchange, including information which is [sometimes] suppressed in non-open or non-free projects, is one of the goals of the GnuTLS project. Please visit https://www.gnutls.org/security.html.


The GnuTLS project maintains mailing lists for users, developers, and commits. Please see https://www.gnutls.org/lists.html.


See the LICENSE file.


Thorough testing is very important and expensive. Often, the developers do not have access to a particular piece of hardware or configuration to reproduce a scenario. Notifying the developers about a possible bug will greatly help the project.

If you believe you have found a bug, please report it to bugs@gnutls.org together with any applicable information.

Applicable information would include why the issue is a GnuTLS bug (if not readily apparent), output from 'uname -a', the version of the library or tool being used, a stack trace if available ('bt full' if under gdb or valgrind output), and perhaps a network trace. Vague queries or piecemeal messages are difficult to act upon and don't help the development effort.

Additional information can be found at the project's manual.


Patches are welcome and encouraged. Patches can be submitted through the bug tracking system or the mailing list. When submitting patches, please be sure to use sources from the git repository, and preferably from the master branch. To create a patch for the project from a local git repository, please use the following commands. 'gnutls' should be the local directory of a previous git clone.

    cd gnutls
    git add the-file-you-modified.c another-file.c
    git commit the-file-you-modified.c another-file.c
    git format-patch

For more information on use of Git, visit https://git-scm.com/

Copying and distribution of this file, with or without modification, are permitted in any medium without royalty provided the copyright notice and this notice are preserved.