i2p.www/pages/jbigi.html

<h1>jbigi</h1>
<p>Using JNI (Java Native Interface), a bit of C code 
(thanks <a href="/user/view/8?PHPSESSID=8efeebc6ed1c132cdcb12821e7ab4a27">ughabugha</a>!), 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.</p>

<h2>Step-by-step instructions</h2>
<ol>
<li>Look on <a href="http://localhost:7655/routerStats.html">http://localhost:7655/routerStats.html</a>
to see what the values for <code>crypto.elGamal.decrypt</code> and <code>crypto.elGamal.encrypt</code> are.
Copy this somewhere so you can compare it later on.</li>

<li>Get the latest sourcecode</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:7655/routerStats.html">http://localhost:7655/routerStats.html</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>