110 lines
2.9 KiB
ReStructuredText
110 lines
2.9 KiB
ReStructuredText
Olm
|
|
===
|
|
|
|
An implementation of the Double Ratchet cryptographic ratchet described by
|
|
https://github.com/trevp/double_ratchet/wiki, written in C and C++11 and
|
|
exposed as a C API.
|
|
|
|
The specification of the Olm ratchet can be found in docs/olm.rst or
|
|
https://matrix.org/docs/spec/olm.html
|
|
|
|
Building
|
|
--------
|
|
|
|
To build olm as a shared library run:
|
|
|
|
.. code:: bash
|
|
|
|
make
|
|
|
|
To run the tests run:
|
|
|
|
.. code:: bash
|
|
|
|
make test
|
|
|
|
To build the javascript bindings, install emscripten from http://kripken.github.io/emscripten-site/ and then run:
|
|
|
|
.. code:: bash
|
|
|
|
make js
|
|
|
|
Release process
|
|
---------------
|
|
|
|
.. code:: bash
|
|
|
|
# Bump version numbers in ``Makefile`` and ``javascript/package.json``
|
|
# Prepare changelog
|
|
git commit
|
|
make clean
|
|
make test
|
|
make js
|
|
npm pack javascript
|
|
VERSION=x.y.z
|
|
scp olm-$VERSION.tgz packages@ldc-prd-matrix-001:/sites/matrix/packages/npm/olm/``
|
|
git tag $VERSION
|
|
git push --tags
|
|
|
|
It's probably sensible to do the above on a release branch (``release-vx.y.z``
|
|
by convention), and merge back to master once complete.
|
|
|
|
|
|
Design
|
|
------
|
|
|
|
Olm is designed to be easy port to different platforms and to be easy
|
|
to write bindings for.
|
|
|
|
It was originally implemented in C++, with a plain-C layer providing the public
|
|
API. As development has progressed, it has become clear that C++ gives little
|
|
advantage, and new functionality is being added in C, with C++ parts being
|
|
rewritten as the need ariases.
|
|
|
|
Error Handling
|
|
~~~~~~~~~~~~~~
|
|
|
|
All C functions in the API for olm return ``olm_error()`` on error.
|
|
This makes it easy to check for error conditions within the language bindings.
|
|
|
|
Random Numbers
|
|
~~~~~~~~~~~~~~
|
|
|
|
Olm doesn't generate random numbers itself. Instead the caller must
|
|
provide the random data. This makes it easier to port the library to different
|
|
platforms since the caller can use whatever cryptographic random number
|
|
generator their platform provides.
|
|
|
|
Memory
|
|
~~~~~~
|
|
|
|
Olm avoids calling malloc or allocating memory on the heap itself.
|
|
Instead the library calculates how much memory will be needed to hold the
|
|
output and the caller supplies a buffer of the appropriate size.
|
|
|
|
Output Encoding
|
|
~~~~~~~~~~~~~~~
|
|
|
|
Binary output is encoded as base64 so that languages that prefer unicode
|
|
strings will find it easier to handle the output.
|
|
|
|
Dependencies
|
|
~~~~~~~~~~~~
|
|
|
|
Olm uses pure C implementations of the cryptographic primitives used by
|
|
the ratchet. While this decreases the performance it makes it much easier
|
|
to compile the library for different architectures.
|
|
|
|
What's an olm?
|
|
--------------
|
|
|
|
It's a really cool species of European troglodytic salamander.
|
|
http://www.postojnska-jama.eu/en/come-and-visit-us/vivarium-proteus/
|
|
|
|
Legal Notice
|
|
------------
|
|
|
|
The software may be subject to the U.S. export control laws and regulations
|
|
and by downloading the software the user certifies that he/she/it is
|
|
authorized to do so in accordance with those export control laws and
|
|
regulations.
|