Trustin a Microsoft Lync Control application is determined by the source of the contextual information offered to the user. If context comes from an installed application, then an offer of trust is present. If context comes from a URL, there is less trust.
Not Trusted - Context Provided by Contextual Link
Contextual Link is the simplest form of context for Microsoft Lync 2010 applications. The developer uses the enumerated value to add a URL to the message. The message recipient will see the following message along with the URL. The recipient should evaluate the circumstances and decide whether to trust the URL:
A contextual link has been provided with this conversation. If the link below looks suspicious do not click the link. http://www.contoso.com
For an example of an application that sends a Contextual Link message, see Walkthrough: Add Context to an Outbound Conversation .
Trusted - Context Provided by Package Registration
Alternatively, provide context by installing a package or application on the sending and receiving client computers. Trust for the application's context is managed by registering a client side application. This type of registration resembles a simple plug-in model. In this case, when the user launches a conversation, the application providing context is already verified. The user can trust the installed application.
There are two package registration methods. Both methods allow the developer to deploy a trusted application to client computers without involvement or management by a system administrator. For information about package registration data, see Registering Contextual Conversation Packages .
In this method, the package registration data is typically added to the Microsoft Lync 2010 registry hive by an installing application. Install registration is also possible using GPO deployment or by the system administrator editing the registry. Use Install Registration for Lync 2010 applications that use a default application to provide message context. For an example that shows how to perform install registration, see Walkthrough: Perform Install Registration for an Extensibility Application .
In this method, the application registration data is added to the Lync 2010 registration pool at run time by the Lync 2010 application. With Run-Time Registration, the developer can choose to manage the contextual experience by selecting one of a number of alternative packages to install. For an example that shows how to perform run-time registration, see Walkthrough: Perform Run-Time Registration for an Extensibility Application .