I'd like to store copy of the activation key used in the registry of the computer that has our software installed on it. I can not find where this value is.
If you are using our "Serial Validation" support then the value of the license key is stored in the Windows Installer public property named PIDKEY.
If you want to encrypt the license key then you can create a custom action to do that. Also, you must have a reverse custom action to decrypt the encrypted key.