Can I insure a second hand iphone, as I have the original receipt of purchase?

Hi, I'm looking to buy a second hand iPhone 4s off a friend. After much research I have realised it is hard to insure a second hand iPhone as it does not have the original receipt. But this one has, and therefore I'm trying to find out if I can insure it? Struggling to find the answer on Google which doesn't happen very often! Also, any suggestions to what company to ensure it with? Thanks.

Added (1). I should add that the receipt is in my friends name so I'm not able to insure the phone 'as new'

Yes you should be able to insure it with a 3rd party company such as protectmybubble.com if you have the original receipt.
You can often add the phone onto household insurance or some bank accounts offer phone insurance.