How to change Canvas Page URL(http) to Secure Canvas Page URL(https) in Facebook Apps?

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Facebook-API

ASP.NET4

I have created an Apps on Facebook.
I need to change the Canvas Page URL i.e. "http://apps.facebook.com/xyz" to secure Canvas Page URL like "https://apps.facebook.com/xyz";

Its a secure URL, when we are logged-in in Facebook and our profile is enabled for secure browsing. But in case no body is logged-in, in that case its not secure URL.
And also i am getting the "http" in case of a user's profile is disabled for secure browsing in Facebook.

Please help me to make this Canvas Page URL to Secure Canvas Page URL.

Regards,
Rahul