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<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="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/guide/System-Libraries-subsystem-guide/ecom/EcomArchitecture/index.html" format="application/java-archive">ECom architecture</xref>.</p>
<fig id="GUID-C5D783F2-8388-4097-8276-BAC6D5B17C2C"><title>ECom framework</title><image href="GUID-231E58F2-7935-462A-B048-51729D8245D4_d0e7325_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="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/guide/platsecsdk/index.html" format="application/java-archive">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="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/guide/System-Libraries-subsystem-guide/ecom/EcomArchitecture/EcomPlatSec.html" format="application/java-archive">ECom and the platform security capability model</xref>. </p>
<p>For examples, see <xref href="http://www.forum.nokia.com/main/resources/technologies/symbian/code_and_examples.html" scope="external">Symbian C++ code and examples</xref> on Forum Nokia.</p>
<section><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="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/guide/Serial-Communications-subsystem-guide/SerialCommsServerClientGuide/index.html" format="application/java-archive">Using Serial Communications Server Client-Side</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="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/guide/Communications-Infrastructure-subsystem-guide/esock/index.html" format="application/java-archive">Using 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="jar:GUID-35228542-8C95-4849-A73F-2B4F082F0C44.jar!/sdk/doc_source/guide/Messaging-subsystem-guide/MessagingGuide/MessagingGuide3/index.html" format="application/java-archive">Message Type Modules</xref>.</p></li>
</ul>
</section>
</conbody></concept>