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{% block title %}jbigi{% endblock %}
{% block content %}<p>Using JNI (Java Native Interface), a bit of C code (thanks ugha!), a little
manual work and a piece of chewinggum it is possible to make the public key
cryptography quite a bit faster.</p>

<h2>Requirements</h2>
<p>This works on Linux, and with a few changes in build.sh probably also on
other platforms. FreeBSD has also been reported to work too. On Kaffee the
speedup is very small, because it already uses native BitInteger internally.
Blackdown seems to cause strange errors. Because you are going to do
compilation, you need JDK; JRE won't work.</p>
<p>The required code is available in CVS and the latest source tarball.</p>
<p>The GNU MP Bignum library (libgmp) needs to be installed, if it isn't
included in your OS / distribution or installed already, it can be received from
<a href="http://www.swox.com/gmp/">http://www.swox.com/gmp/</a>. Even if you
have already installed it as binary, it might still be worth a try to compile
GMP yourself, since then it will be able to use the specific instructions of
your processor. The latest GMP 4.2.2 is also
possible to be used instead of GMP 4.1.4. But latest GMP 4.2.2 needs more
testing before setting the default requirement for building jbigi.jar.</p>

<h2>Step-by-step instructions</h2>
<ol>
<li>Look on <a href="http://localhost:7657/oldstats.jsp">http://localhost:7657/oldstats.jsp</a>
to see what the values for <code>crypto.elGamal.decrypt</code> and
<code>crypto.elGamal.encrypt</code> are. The numbers are times in milliseconds. Copy these somewhere so you can compare
them later on.</li>
<li>Get the latest sourcecode of I2P out of the monotone database mtn.i2p2.de</li>
<li>Inside the source tree change directory to: <code>core/c</code></li>
<li>Take a look at <code>build.sh</code>, if your <code>JAVA_HOME</code>
environment variable is set and you are using Linux then it might just work.
Otherwise change the settings.</li>
<li>Run <code>build.sh</code><br/>
A file named <code>libjbigi.so</code> should be created in the current
directory. If this doesn't happen and/or you get errors then please report
them.<br/>
Also some tests are done. Read the final lines of output for some additional
info, it will be something like this:
<pre>
native run time:  5842ms ( 57ms each)
java run time:   41072ms (406ms each)
native = 14.223802103622907% of pure java time
</pre>
If the native is indeed 5-7x faster then it looks all good. If not, please
report.</li>
<li>Copy <code>libjbigi.so</code> to your i2p directory</li>
<li>Restart your I2P programs.</li>
<li>On
<a href="http://localhost:7657/oldstats.jsp">http://localhost:7657/oldstats.jsp</a>
the <code>crypto.elGamal.decrypt</code> and <code>crypto.elGamal.encrypt</code>
should be a lot faster.</li>
</ol>

<p>Feedback is appreciated</p>
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