How do I prevent a skillful user from getting the sub-key out of HTML source when using the PubNub Javascript library?

The best way to ensure data security is by using a secure key. Properly securing the client side with entropic channel naming and full SSL 2048-bit encryption. To get started, see the PubNub Cryptography pageTo further secure access to your PubNub channels, you should implement the PubNub Access Manager.