2015-06-27 01:15:23 +02:00
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Olm
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===
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2015-06-26 18:55:32 +02:00
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2015-06-28 18:00:01 +02:00
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An implementation of the cryptographic ratchet described by
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2015-06-26 19:26:01 +02:00
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https://github.com/trevp/axolotl/wiki, written in C++11 and exposed as a C API
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2015-06-26 18:55:32 +02:00
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2015-10-03 00:57:46 +02:00
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The specification of the Olm ratchet can be found in docs/olm.rst or
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https://matrix.org/docs/spec/olm.html
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2015-06-26 18:55:32 +02:00
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Building
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--------
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2015-06-27 01:15:23 +02:00
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To build olm as a shared library run:
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2015-06-26 18:55:32 +02:00
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.. code:: bash
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./build_shared_library.py
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To run the tests run:
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.. code:: bash
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./test.py
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2015-06-27 04:35:07 +02:00
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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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2015-06-26 18:55:32 +02:00
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.. code:: bash
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javascript/build.py
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Design
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------
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2015-06-27 01:15:23 +02:00
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Olm is designed to be easy port to different platforms and to be easy
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2015-06-26 18:55:32 +02:00
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to write bindings for.
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Error Handling
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~~~~~~~~~~~~~~
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2015-06-27 01:15:23 +02:00
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All C functions in the API for olm return ``olm_error()`` on error.
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2015-06-26 18:55:32 +02:00
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This makes it easy to check for error conditions within the language bindings.
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Random Numbers
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~~~~~~~~~~~~~~
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2015-06-27 01:15:23 +02:00
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Olm doesn't generate random numbers itself. Instead the caller must
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2015-06-26 18:55:32 +02:00
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provide the random data. This makes it easier to port the library to different
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platforms since the caller can use whatever cryptographic random number
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generator their platform provides.
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Memory
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~~~~~~
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2015-06-27 01:15:23 +02:00
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Olm avoids calling malloc or allocating memory on the heap itself.
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2015-06-26 18:55:32 +02:00
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Instead the library calculates how much memory will be needed to hold the
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output and the caller supplies a buffer of the appropriate size.
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Output Encoding
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~~~~~~~~~~~~~~~
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Binary output is encoded as base64 so that languages that prefer unicode
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strings will find it easier to handle the output.
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Dependencies
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~~~~~~~~~~~~
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2015-06-27 01:15:23 +02:00
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Olm uses pure C implementations of the cryptographic primitives used by
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2015-06-26 18:55:32 +02:00
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the ratchet. While this decreases the performance it makes it much easier
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to compile the library for different architectures.
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2015-06-27 01:15:23 +02:00
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What's an olm?
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~~~~~~~~~~~~~~
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It's a really cool species of European troglodytic salamander.
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Matthew once tried to climb into a pool full of them in Postojnska Jama.
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http://www.postojnska-jama.eu/en/about-the-cave/meet-the-dragon-s-offspring/
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