Firstly the link JS code is minified to reduce file size that code not served for purpose of read, reuse, modify by programmer.
So you have to reverse-engineering this code if you want to call e.prototype.encrypt function.
Please follow the bellow step to unminify code.
- copy all minified code from https://hpc.freedompay.com/api/v1.4/cdn/internal/default_min.js?v=20.42.1-release0003.898
- open https://jsfiddle.net/
- paste code JavaScript pane at the bottom left
- click 'tidy' button at the upper right in JavaScript pane.