Secure the code and enable the CEP extension to function with a license key

Hello everyone,

I have created an extension for Adobe Illustrator and would like to sell it on gumroad.com.

1. How can I secure my code, such as encrypting it?
2. How can I implement a licensing system, where gumroad provides a license key to activate the extension?

I hope someone can help me with this, and I would be grateful for any assistance.