A Watermarking Protocol Based on Blockchain

Digital watermarking can be used to implement mechanisms aimed at protecting the copyright of digital contents distributed on the Internet. Such mechanisms support copyright identification and content tracking by enabling content providers to embed perceptually invisible watermarks into the distributed copies of contents. They are employed in conjunction with watermarking protocols, which define the schemes of the web transactions by which buyers can securely purchase protected digital contents distributed by content providers. In this regard, the ``buyer friendly'' and ``mediated'' watermarking protocols can ensure both a correct content protection and an easy participation of buyers in the transactions by which to purchase the distributed contents. They represent a valid alternative to the classic ``buyer and seller'' watermarking protocols documented in the literature. However, their protection schemes could be further improved and simplified. This paper presents a new watermarking protocol able to combine the ``buyer friendly'' and ``mediated'' design approach with the blockchain technology. The result is a secure protocol that can support a limited and balanced participation of both buyers and content providers in the purchase transactions of protected digital contents. Moreover, the protocol can avoid the direct involvement of trusted third parties in the purchase transactions. This can reduce the actual risk that buyers or sellers can violate the protocol by illicitly interacting with trusted third parties. In fact, such peculiarities make the proposed protocol suited for the current web context.