I can only say Harris is secure and limited by how securely system admins and site managers keep, store, and distribute the keys/dongles.
Like a password, if strong enough, only you know it, it is never divulged or written, it can be considered secure.
You divulge that password to 3 people, then 4 have access, any one of those 4 leak, you are no longer secure.
Those dongles are very limited, each one with a hard coded serial number. They can be stolen, copied, sold, but that is the compromise.
Then you have the security breach.