Hi,

I'm new to the Bitcoin protocole.
So please forgive this newbie question.

I'd like to know if, without providing some kind of "escrow wallet", a intermediary can know if a buyer has actually send an amount of money to another user? If the buyer and/or seller do provide some required information?

For example a buyer goes to my website where is directly displayed the QR Code of a Bitcoin address from a seller. The buyer buys something costing 0.002 Bitcoins from that seller... Is there a way for the buyer and/or the seller to provide me a way to make sure the transaction actually occured or not?

I know most intermediaries, such as exchanges, require you to first deposite money on a special wallet on their side so they can validate your transactions. But is such validation possible when a direct tranfert is made from a buyer to a seller? Again, if both parties do agree for the transaction to be validated?

I could of course ask the seller to confirm that he has received the money... But I would prefere something more robust, something that would protect the buyer too.

Thanks in advance for any tips, links or articles!