GNU SASL README -- Important introductory notes.
Copyright (C) 2002-2021 Simon Josefsson
See the end for copying conditions.

GNU SASL is an implementation of the Simple Authentication and
Security Layer (SASL) framework and a few common SASL mechanisms.
SASL is used by network servers (e.g., IMAP, SMTP, XMPP) to request
authentication from clients, and in clients to authenticate against
servers.

GNU SASL consists of a C library (libgsasl), a command-line
application (gsasl), and a manual.  The library supports the
ANONYMOUS, CRAM-MD5, DIGEST-MD5, EXTERNAL, GS2-KRB5, GSSAPI, LOGIN,
NTLM, OPENID20, PLAIN, SCRAM-SHA-1, SCRAM-SHA-1-PLUS, SCRAM-SHA-256,
SCRAM-SHA-256-PLUS, SAML20, and SECURID mechanisms.

The GNU SASL Library (lib/) is licensed under the GNU Lesser General
Public License (LGPL) version 2.1 (or later).  See the file
COPYING.LIB.  The GNU project typically uses the GNU General Public
License (GPL) for libraries, and not the LGPL, but for this project we
decided that we would get more help from the community if we used the
LGPLv2.1+, as other free SASL implementations exists.  See also
<https://www.gnu.org/licenses/why-not-lgpl.html>.

The command-line application and test suite (src/ and tests/) are
licensed under the GNU General Public License license version 3.0 (or
later).  See the file COPYING.

The documentation (doc/) is licensed under the GNU Free Documentation
License version 1.3 (or later).  See the file doc/fdl-1.3.texi.

If you need help to use GNU SASL, or wish to help others, you are
invited to join our mailing list help-gsasl@gnu.org, see
<https://lists.gnu.org/mailman/listinfo/help-gsasl>.

Currently there is some support for the following mechanisms:

  - CRAM-MD5 (RFC 2195)
  - EXTERNAL (RFC 2222)
  - GSSAPI (RFC 2222, requires GSS, Heimdal or MIT Kerberos)
  - ANONYMOUS (RFC 2245)
  - PLAIN (RFC 2595)
  - SECURID (RFC 2808)
  - DIGEST-MD5 (RFC 2831)
  - SCRAM-SHA-1 and SCRAM-SHA-1-PLUS (RFC 5802)
  - SCRAM-SHA-256 and SCRAM-SHA-256-PLUS (RFC 7677)
  - GS2-KRB5 (RFC 5801, no CB, requires GSS, Heimdal, or MIT Kerberos)
  - SAML20 (RFC 6595)
  - OPENID20 (RFC 6616)
  - LOGIN (non-standard)
  - NTLM (non-standard, client only, requires Libntlm)

The library should be portable to C89 platforms.  The command-line
application requires POSIX or Windows for network communication.

Things left to do below.  If you like to start working on anything,
please let me know so work duplication can be avoided.

  * Support channel bindings in GS2.
  + Authentication infrastructure implementing the callbacks for
    PAM, Kerberos, SQL, etc.  Separate project?  GNU Mailutils has
    some starting points for this, but the API is inflexible.
  + Provide standard callbacks for tty, GTK, gpg-agent etc.  Probably
    should be a separate library.
  + Port applications to use libgsasl
  - Bug: If gsasl_decode is handed a string longer than one SASL
    token, the remaining data will be discarded.  This means if the
    sender packed two SASL tokens in one network packet, only the
    first will be seen.  The en/de-code functions should buffer the
    left over data until the next invocation.  Later: it isn't clear
    that people actually need the security layer feature, and it seems
    better to punt to TLS.
  - Security layer improvements (e.g., DES and AES in DIGEST-MD5).
  - Cleanup code, possibly by using some string abstraction library.
  - Privacy separation (authenticate in one process, pass state to another).
  - Improve documentation
  - Port to Cyclone? CCured?

For updates to the project, see <https://www.gnu.org/software/gsasl/>.

For any copyright year range specified as YYYY-ZZZZ in this package
note that the range specifies every single year in that closed interval.

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