11-05-2012, 03:51 PM
A Privacy-Preserving Buyer–Seller Watermarking Protocol Based on Priced Oblivious Transfer
A Privacy-Preserving Buyer–Seller Watermarking.docx (Size: 17.19 KB / Downloads: 36)
Abstract:
Buyer–seller watermarking protocols are asymmetric fingerprinting schemes in which the fingerprint is embedded by means of watermarking techniques. The basic idea is that each buyer obtains a slightly different copy of the digital content. Such difference, the watermark, does not harm the quality of the copy and cannot be removed by the buyer. Some buyer–seller watermarking protocols also provide buyers with anonymity different approach to provide privacy protection in buyer–seller watermarking protocols. In our approach, based on oblivious e-commerce protocols, buyers are authenticated by the seller, but the seller does not learn which items are purchased. Buyer–seller watermarking protocols allow copyright protection of digital goods. To protect privacy, some of those protocols provide buyers with anonymity. However, anonymous-commerce protocols pose several disadvantages, like hindering customer management or requiring anonymous payment mechanisms. Additionally, no existing buyer–seller watermarking protocol provides fair exchange. This overcomes the disadvantages of anonymous purchase. Since buyers are authenticated, customer management is eased and currently deployed methods of payment can be utilized. Privacy-preserving buyer–seller watermarking (PBSW) protocols, is defined formally and i.e., buyer–seller watermarking protocols in which the seller does not learn which items are purchased. We also provide a construction of such a protocol based on existing techniques for asymmetric watermark embedding and on priced oblivious transfer (POT). Anonymous buyer–seller watermarking protocols consist of a cheap initialization phase and expensive transfer phases. Therefore, our protocol is more convenient in resource constrained settings because the initialization phase needs to be run only once, and later on a lot of very cheap purchase phases can be carried out.
Existing System:
Existing techniques for asymmetric watermark embedding and on priced oblivious transfer (POT). (POT is the key building block of oblivious e-commerce protocols.) Finally, we explain how to extend our protocol to provide fair exchange. No existing buyer–seller watermarking protocol provides fair exchange. A protocol based on priced oblivious transfer and on existing techniques for asymmetric watermark embedding. Existing secure POT schemes follow an assisted decryption approach in which the interaction between a seller and a buyer is divided into an initialization phase and several purchase phases. In the initialization phase, encrypts the messages to be sold and sends the cipher texts to. In each purchase phase, helps to decrypt one of the cipher texts via an interactive protocol. To allow for payments, existing POT schemes employ a prepaid mechanism. In the initialization phase, makes an initial deposit to and in each purchase phase, debits the price of the message from the deposit and proves to that the remaining deposit is nonnegative. Is able to verify those facts by learning neither the price of the message nor the new value of the deposit. Our PBSW protocol combines POT with existing techniques for asymmetric watermark embedding. In particular, we use a simplified version of the buyer–seller watermarking protocol in which buyers are not provided with anonymity.
Problem Description:
• anonymous-commerce protocols pose several disadvantages, like hindering
customer management or requiring anonymous payment mechanisms.
• possible disadvantages, one can argue that the seller can find it difficult to learn which items are more demanded
Proposed system:
Anonymous buyer–seller watermarking protocols consist of a cheap initialization phase and expensive transfer phases. Therefore, our protocol is more convenient in resource constrained settings because the initialization phase needs to be run only once, and later on a lot of very cheap purchase phases can be carried out. Fingerprinting schemes deter people from illegally redistributing digital copies by enabling the seller of the data to identify the buyer. A scheme is said to be collusion-resistant when it prevents a collusion of buyers up to a maximum size from producing no traceable copies. In asymmetric fingerprinting schemes the fingerprinted copy is only known to the buyer at the end of the purchase protocol. Thanks to this property, when the seller finds a redistributed copy, he can present it as a proof of the buyer’s misbehavior, and the buyer cannot claim that the copy was produced by the seller. In order to protect privacy, fingerprinting protocols that provide buyers with anonymity have been proposed Buyer–seller watermarking protocols are asymmetric fingerprinting schemes in which the fingerprint is embedded by means of watermarking techniques. The basic idea is that each buyer obtains a slightly different copy of the digital content. Such difference, the watermark, does not harm the quality of the copy and cannot be removed by the buyer. Some buyer–seller Watermarking protocols also provide buyers with anonymity e-commerce protocols are usually analyzed in order to prove their fairness .Roughly speaking, fair exchange ensures that, at the end of the transaction, either the seller receives the payment and the buyer receives the purchased item, or both parties receive nothing. However, to the best of our knowledge, no fair buyer–seller watermarking protocol has been proposed. a different approach is proposed to provide privacy protection in buyer–seller watermarking protocols. In our approach, based on oblivious e-commerce protocols, buyers are authenticated by the seller, but the seller does not learn which items are purchased. This overcomes the disadvantages of anonymous purchase. Since buyers are authenticated, customer management is eased and currently deployed methods of payment can be utilized. As possible disadvantages, one can argue that the seller can find it difficult to learn which items are more demanded this information can be obtained by other means, e.g., by conducting marketing research a transformation that takes as input a secure POT scheme and turns it into an optimistic fair POT scheme has been proposed. This transformation requires a neutral third party, an adjudicator, who is only involved in case of dispute between a seller and a buyer (hence the protocol is called optimistic).Other fair e-commerce protocols that do not protect privacy also require the involvement of a third party. The transformation is based on the use of verifiably encrypted signatures (VES). Roughly speaking, a VES is a signature encrypted under the public key of the adjudicator that can be publicly verified; i.e., the verifier can check that the cipher text contains a valid signature without the secret key of the adjudicator To evaluate the performance of the whole PBSW protocol, implement the POT scheme proposed in a workstation equipped with an IntelCore2Duo processor at 3 GHz and4 Gbyte of RAM. All the functionalities are implemented in the C programming language. a PBSW protocol, i.e., a protocol that allows copyright protection and in which buyers purchase from sellers without the seller learning the items they buy. Furthermore, have also described how to extend the protocol to provide both buyers and sellers with optimistic fair exchange.