I was trying to work out why parts of this website <http://www.islandsmultimedia.com> would appear as blank pages. It turns out they employ something called "HTML Protector" to make the source code unreadable.
First a general comment: encrypting HTML is not possible. I can load any "protected" page in any modern browser and see the source code in no time by typing
The marketing of the HTML Protector software and relatives may be clever but their products are basically bogus. HTML is designed to be open. It is part of the reason why the Web developed as quickly as it did.
The "encryption" used by "HTML Protector" is as far as I can see to take each character in a string, lookup ASCII value, XOR it, turn the new number into a character and URL encode the whole output.
The reason why Opera does not display the page is that the script specifically detects Opera and decides it will display blank page instead:
I suppose they have decided that Opera users are too smart and might get around their "protection".