Patent ID: 8924308

Claim:
A computer implemented method comprising: receiving funds from a buyer at a trading platform comprising a computer system; encrypting, by the computer system using a seller key, a first message that includes a seller secret; encrypting, by the computer system using a buyer key, a second message that includes a buyer secret and the encrypted first message; providing, by the computer system, the buyer with the encrypted second message; detecting, by the computer system prior to delivery of a virtual item, a presence of the buyer at a virtual location in a game where an exchange of the virtual item between the buyer and seller is to occur; authenticating the buyer, by the computer system, using the buyer secret; in response to and after authenticating the buyer and detecting the buyer at the virtual location, sending a third message to the seller to go to the virtual location; detecting, by the computer system, that the seller arrives at the virtual location; delivering the virtual item from the seller to the buyer at the virtual location; delivering the encrypted first message from the buyer to the seller and obtaining the seller secret by decrypting by the seller the encrypted first message; authenticating, by the computer system, the seller using the seller secret; and supplying, by the computer system, the seller with the funds.