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Olm
===
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An implementation of the cryptographic ratchet described by
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https://github.com/trevp/axolotl/wiki, written in C++11 and exposed as a C API
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The specification of the Olm ratchet can be found in docs/olm.rst or
https://matrix.org/docs/spec/olm.html

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Building
--------

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To build olm as a shared library run:
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.. code:: bash

    ./build_shared_library.py

To run the tests run:

.. code:: bash

   ./test.py


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To build the javascript bindings, install emscripten from http://kripken.github.io/emscripten-site/ and then run:
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.. code:: bash

    javascript/build.py

Design
------

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Olm is designed to be easy port to different platforms and to be easy
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to write bindings for.

Error Handling
~~~~~~~~~~~~~~

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All C functions in the API for olm return ``olm_error()`` on error.
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This makes it easy to check for error conditions within the language bindings.

Random Numbers
~~~~~~~~~~~~~~

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Olm doesn't generate random numbers itself. Instead the caller must
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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
~~~~~~

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Olm avoids calling malloc or allocating memory on the heap itself.
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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
~~~~~~~~~~~~

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Olm uses pure C implementations of the cryptographic primitives used by
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the ratchet. While this decreases the performance it makes it much easier
to compile the library for different architectures.
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What's an olm?
~~~~~~~~~~~~~~

It's a really cool species of European troglodytic salamander.
Matthew once tried to climb into a pool full of them in Postojnska Jama.
http://www.postojnska-jama.eu/en/about-the-cave/meet-the-dragon-s-offspring/