How to configure the validation mechanism for link tracking in Portrait Dialogue

In version 6.0 SP1 Portrait Dialogue introduced a validation mechanism for link tracking.
This ensures the integrity of tracked URLs in emails and other messages, and protects against phishing attacks. The mechanism uses a checksum (in the URL) for validating that the destination URL is original and has not been tampered with.

The validation mechanism is turned off by default to ensure compatibility with URLs in messages that have been sent out in previous versions of Portrait Dialogue. 

To turn the validation on, open the web.config file (located in: <WebUtilities>\LT\) and set the <checkSum enable> value to true: 
User-added image

The commented part: 
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contains settings to provide a redirect URL for use if the checksum is not correct or missing. 
There is a default section in the configuration file, but there may also be a section for each database instance. Any instance sections will override the default values. 

In the web.config file there is also a commented part that tells briefly how to handle CheckSum:

<!-- CheckSum Handling
          - enable: Enables or disables check sum for a given installation
          - instances: List of instances with their specific settings
                - instance: Instance with its specific setting
                      - name: Unique instance name
                      - enable: Enables or disables check sum for a given instance
                      - defaultRedirect [optional]: Default page shown in case checksum fails. 
                                                    Start the path with '~' if you want an error page located inside the web application and 
                                                    'http://' if you want a global error page. Default is "~/ErrorPages/Redirect.aspx" -->

More information can be found in the Server Installation Guide, the Server Upgrade Guide and the Reference Guide.
UPDATED:  July 31, 2017