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<!DOCTYPE concept
  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
<concept id="GUID-2E986A81-F094-4F1D-9ECB-6A325CFA5BB4" xml:lang="en"><title>Plug-ins</title><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>Plug-ins connect to the system using the EPOC Component Object
Model (ECom). ECom is based on client/server architecture and provides
services to instantiate, resolve, and destroy instances of plug-ins
at run time. For more information, see the <xref href="GUID-30201A05-C6CE-5D34-9BDF-CDA4EE44878D.dita">ECom Architecture</xref>.</p>
<fig id="GUID-C5D783F2-8388-4097-8276-BAC6D5B17C2C"><title>ECom framework</title><image href="GUID-231E58F2-7935-462A-B048-51729D8245D4_d0e12411_href.png"/></fig>
<p>A hostile or malfunctioning plug-in may cause crashes or security
leaks, even on otherwise well-tested applications. The <xref href="GUID-4BFEDD79-9502-526A-BA7B-97550A6F0601.dita">platform security</xref> architecture protects the processes by verifying that the plug-in
has equal or greater set of capabilities than the process in which
it is loaded. For more information, see the <xref href="GUID-9E4D75C0-D797-5541-8E52-3C6D154CC74A.dita">ECom and the Platform
Security Architecture</xref>. </p>
<p>For examples, see <xref href="GUID-E59A469E-A2B5-5DF0-BA7E-C50D4A38CCAA.dita">Plug-in Framework
(ECom) Examples</xref>.</p>
<section id="GUID-2268BF28-467F-409F-B68C-5D361E8C5FF0"><title>Communication
plug-ins</title>
<p>It is possible to use plug-ins to implement additional functionality
to serial, socket, and messaging frameworks. These plug-ins are especially
important for security because they deal with communication.</p>
<ul>
<li><p>For serial communication there are serial protocol
modules (CSY modules ), which are loaded by the Serial Comms Server.
For more information on serial communication, see <xref href="GUID-9B83CDD4-FC94-51A0-AC67-CD04BCAFEF08.dita">Serial Communications
Server</xref>.</p></li>
<li><p>For socket-based communication there are protocol
modules (PRT), which are loaded by the Socket Server. For more information
on socket-based communication, see <xref href="GUID-61E0CD76-A2E3-5066-84A8-146EECA8ADCD.dita">Socket Server</xref>.</p></li>
<li><p>For messaging there are Message Type Modules (MTM),
which include both client and server components. MTMs are a set of <codeph>dll</codeph>s rather than a single <codeph>dll</codeph>. For more
information, see <xref href="GUID-8B843382-D27A-5E36-8F60-304903F3AA41.dita">Message Type Module</xref>.</p></li>
</ul>
</section>
</conbody></concept>