Priced Oblivious Transfer: How to Sell Digital Goods

Abstract. We consider the question of protecting the privacy of customers buying digital goods. More specifically, our goal is to allow a buyer to purchase digital goods from a vendor without letting the vendor learn what, and to the extent possible also when and how much, it is buying. We propose solutions which allow the buyer, after making an initial deposit, to engage in an unlimited number of priced oblivioustransfer protocols, satisfying the following requirements: As long as the buyer’s balance contains sufficient funds, it will successfully retrieve the selected item and its balance will be debited by the item’s price. However, the buyer should be unable to retrieve an item whose cost exceeds its remaining balance. The vendor should learn nothing except what must inevitably be learned, namely, the amount of interaction and the initial deposit amount (which imply upper bounds on the quantity and total price of all information obtained by the buyer). In particular, the vendo...

• Type: Conference
• Year: 2001
• Where: EUROCRYPT
• Authors: William Aiello, Yuval Ishai, Omer Reingold
• Keywords: Buyer’s Balance, Cryptology, EUROCRYPT 2001, Initial Deposit, Vendor