I like the first one because I don't think it is so complicated a coding project. From the interface side the URL below forces the user to get view the certificate, if they are qualified.
I sort of remember that view.php is the standard way to open up an activity. Guessing if their is no action=get as a variable in the activity module code, it does not matter. And if there is, that is probably where we want to send the student.
I will let you serious developers have at it Time to take my puppy for a long walk in the woods.