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 The SSH library

1* Why ?

Why not ? :) I've began to work on my own implementation of the ssh protocol
because i didn't like the currently public ones.
Not any allowed you to import and use the functions as a powerful library, 
and so i worked on a library-based SSH implementation which was non-existing
in the free and open source software world.

2* How/Who ?

If you downloaded this file, you must know what it is : a library for
accessing ssh client services through C libraries calls in a simple manner.
Everybody can use this software under the terms of the LGPL - see the COPYING

If you ask yourself how to compile libssh, please read INSTALL before anything.

3* Where ?


4* API Changes !

Changes between 0.4 and 0.5

We use the ssh_ prefix as namespace for every function now. There is a legacy.h
which could be used to get the old function names.

Changes between 0.3 and 0.4

We changed libssh to be typesafe now:

SSH_SESSION *session -> ssh_session session
SFTP_SESSION *sftp -> sftp_session sftp
CHANNEL *channel -> ssh_channel channel
STRING *string -> ssh_string string

The options structure has been removed and there is a new function. This
function can set all available options now. You can find the enum in the
header file and it is documented. Example:

ssh_options_set(session, SSH_OPTIONS_HOST, "localhost");

5* Copyright policy

libssh is a project with distributed copyright ownership, which means we prefer
the copyright on parts of libssh to be held by individuals rather than
corporations if possible. There are historical legal reasons for this, but one
of the best ways to explain it is that it’s much easier to work with
individuals who have ownership than corporate legal departments if we ever need
to make reasonable compromises with people using and working with libssh.

We track the ownership of every part of libssh via git, our source code control
system, so we know the provenance of every piece of code that is committed to

So if possible, if you’re doing libssh changes on behalf of a company who
normally owns all the work you do please get them to assign personal copyright
ownership of your changes to you as an individual, that makes things very easy
for us to work with and avoids bringing corporate legal departments into the

If you can’t do this we can still accept patches from you owned by your
employer under a standard employment contract with corporate copyright
ownership. It just requires a simple set-up process first.

We use a process very similar to the way things are done in the Linux Kernel
community, so it should be very easy to get a sign off from your corporate
legal department. The only changes we’ve made are to accommodate the license we
use, which is LGPLv2 (or later) whereas the Linux kernel uses GPLv2.

The process is called signing.

How to sign your work

Once you have permission to contribute to libssh from your employer, simply
email a copy of the following text from your corporate email address to:


libssh Developer's Certificate of Origin. Version 1.0

By making a contribution to this project, I certify that:

(a) The contribution was created in whole or in part by me and I
    have the right to submit it under the appropriate
    version of the GNU General Public License; or

(b) The contribution is based upon previous work that, to the best of
    my knowledge, is covered under an appropriate open source license
    and I have the right under that license to submit that work with
    modifications, whether created in whole or in part by me, under
    the GNU General Public License, in the appropriate version; or

(c) The contribution was provided directly to me by some other
    person who certified (a) or (b) and I have not modified it.

(d) I understand and agree that this project and the contribution are
    public and that a record of the contribution (including all
    metadata and personal information I submit with it, including my
    sign-off) is maintained indefinitely and may be redistributed
    consistent with the libssh Team's policies and the requirements of
    the GNU GPL where they are relevant.

(e) I am granting this work to this project under the terms of the
    GNU Lesser General Public License as published by the
    Free Software Foundation; either version 2.1 of
    the License, or (at the option of the project) any later version.


We will maintain a copy of that email as a record that you have the rights to
contribute code to libssh under the required licenses whilst working for the
company where the email came from.

Then when sending in a patch via the normal mechanisms described above, add a
line that states:

   Signed-off-by: Random J Developer <random@developer.example.org>

using your real name and the email address you sent the original email you used
to send the libssh Developer’s Certificate of Origin to us (sorry, no
pseudonyms or anonymous contributions.)

That’s it! Such code can then quite happily contain changes that have copyright
messages such as:

   (c) Example Corporation.

and can be merged into the libssh codebase in the same way as patches from any
other individual. You don’t need to send in a copy of the libssh Developer’s
Certificate of Origin for each patch, or inside each patch. Just the sign-off
message is all that is required once we’ve received the initial email.

Have fun and happy libssh hacking!

The libssh Team