Duty and GST for online cigarettes?

i was wondring how much is the Duty and GST for Cigarettes that i buy online.

GST in Canada is 5%, does that apply to online products to, or it has different rate ?
and what about duty.. how much is that .

Lets say if i ordered 3 Cartoons (600 Cigarettes)..

and how they will know how much i paid for the cartoon, thanks

Carton of 200 cigarettes (Ontario)

* The federal excise duty is $5.50.
* The federal excise tax is $2.66.
* The provincial tobacco tax is $4.70
* There is a 8% provincial sales tax
* The federal G.S.T. adds 5%

"They" will know how much you paid because the seller will include an invoice.