This section of your Site’s settings contains your Site’s Shared Key. Your Site’s “Shared Key” is a value that only you and Chargify know. It is used to generate unguessable URLs for the pages hosted by Chargify that your customers may interact with - pages like Public Signup Pages and Self-Service Pages.
Note: currently only the Self-Service Page takes advantage of these new, programmatic URLs.
The Shared Key is combined with other known values to create a message. That message is then encoded using the SHA-1 algorithm to generate a digest. A portion of that digest becomes a “token” that is used to authenticate the URL. (SHA-1 produces a 40 character digest, but we only check the first 10)
For more information on how to generate tokens, please see our Self-Service Pages documentation on generating tokens and unique URLs.