You must sign your cabinet file whenever one of the following conditions apply:
Use the signcode tool to sign a cabinet file. You can specify one of the three basic security levels (High, Medium, or Low) or you can set custom permissions by creating a permissions .ini file for use with signcode. The finer-grained permissions you can assign in this .ini file enable you to reduce the access allowed to the bare minimum required by your project. For instructions and examples, see Signing Cabinet Files with Java Permissions.
You can use a test certificate when signing your code for development purposes, but you must obtain an actual certificate before deploying your application. Certificates can be obtained from a Certificate Authority. For more information on Microsoft's code-signing technology, see http://www.microsoft.com/security/default.asp .