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<concept id="GUID-1293DE8C-E803-4ADF-9FA8-862519337331" xml:lang="en"><title>Software
installer</title><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>End users can install new software from a variety of sources: through
e-mail, Internet downloads, multimedia messaging service (MMS) and WAP push
messages, infrared and Bluetooth connections, PC Suite, and removable memory
cards. The diversity of software vendors and delivery channels requires a
sophisticated system for managing installed software.</p>
<p>The Symbian <i>Software Installer</i> uses <i>digital signatures</i> and <i>certificates</i> to
authenticate that the application being installed on a mobile device is from
a known vendor. The signature can be obtained through the <xref href="https://www.symbiansigned.com/app/page" scope="external">Symbian
Signed</xref> process, and the default certificates installed in the mobile
device act as root certificates. During installation the signature is validated
against the certificates. If they match, the application is installed and
the requested <xref href="GUID-6971B0A2-F79B-4E05-8AF3-BB1FC1932A22.dita">capabilities</xref> are
stored in the executable, assuming that the root certificate can grant the
capabilities. Only <i>user capabilities</i> can be granted to unsigned or
self-signed applications, and these are always confirmed by the user. </p>
<note>
<p>The end users have an option to cancel the installation if they detect
that the vendor of the software package and certificate authority are not
trustworthy. This is especially important when installing security-related
components (for example, VPN clients, firewalls and virus scanners) or other
business-related software.</p>
</note>
<p>The Software Installer ensures that no two applications have the same <xref href="GUID-3B6E25F7-C1A8-461F-97F7-421DB559BC98.dita#GUID-3B6E25F7-C1A8-461F-97F7-421DB559BC98/GUID-EEC50FC0-46D5-4ED7-AD95-67430D5EC652">SID</xref> value
on a particular target device. The Software Installer has the <codeph>TCB</codeph> capability
to read and modify content in the <xref href="GUID-B9414AE8-820E-4CA5-A9C4-29560CD6F2EF.dita"><codeph>\sys</codeph> </xref> folder
and all its subfolders, which means that you can write to third-party application
executables in the <codeph>\sys\bin</codeph> folder when they are installed
through the Software Installer.</p>
<p>For more information on the Software Installer, see <xref href="GUID-8E160B29-18C4-574B-9259-9A8E958CDA91.dita">Secure
Software Install Tools</xref>.</p>
<p>The following figure illustrates the steps of software installation:</p>
<fig id="GUID-98820420-7C7A-46EC-9DE4-EA3F5FFD39A8"><title>Installation process for signed packages</title><image href="GUID-85291DF3-C134-4231-938A-C20DD122AB7D_d0e12428_href.png"/></fig>
<p>The Software Installer can install the following types of packages:</p>
<ul>
<li><p>signed <codeph>sis</codeph> packages</p></li>
<li><p>Java archives (JAR) run by a Java virtual machine</p>
</li>
<li><p>Web Runtime widgets</p></li>
</ul>
<p>The Software Installer recognizes different devices, which allows you
to define the platforms and devices to which the software can be installed.</p>

<p>If you receive an error message when using the Software Installer, see <xref href="http://developer.symbian.org/wiki/index.php/Troubleshooting_Installation_Errors.dita">Troubleshooting
Installation Errors</xref> at the Symbian Foundation.</p>
</conbody></concept>