Based on secure watermark embedding,a new buyer-seller watermarking protocol is proposed. The proposed protocol permits buyers to anonymously buy digital products,and it can protect buyer's right in the whole process of transaction. At the same time it can also solve piracy tracking problem,and the unbinding problem between watermarking,digital products and a special transaction.Once the seller finds an unauthorized copy,he / she can identify the buyer from a watermark in the unauthorized copy,and then prov...