Blockchain and Cloud to Overcome the Problems of Buyer and Seller Watermarking Protocols

Copyright protection of digital content has become a problem not only for web content providers but also for ordinary web users who like to publish their digital contents on social or user generated content platforms. Among the possible solutions to such a problem, digital watermarking, in conjunction with watermarking protocols, appears to be a valid alternative to current DRM (digital rights management) systems. In fact, watermarking based solutions insert perceptually invisible copyright information into the copies of contents published or distributed on the web in order to track them. Such insertions are carried out according to the watermarking protocols, which have evolved over the years from the classic “buyer and seller” paradigm into a simpler and versatile “buyer friendly” and “mediated” approach. However, such an approach cannot exploit the new technologies that characterize the current Internet. This paper presents a new watermarking protocol able to adapt the “buyer friendly” and “mediated” approach to the use of innovative technologies such as cloud platforms and blockchain. In this way, (1) content providers and common web users can take advantage of the computing and storage resources made available by cloud platforms; (2) the involvement of trusted third parties in the protocols can be reduced by using blockchain without complicating the protection scheme. In fact, these two goals make the protocol particularly suited for the current Internet.

A Watermarking Protocol Based on Blockchain

Digital watermarking can be used to implement mechanisms aimed at protecting the copyright of digital content 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 content. They are employed in conjunction with watermarking protocols, which define the schemes of the web transactions by which buyers can securely purchase protected digital content 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 content. 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 content. 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.

A Cloud-User Watermarking Protocol Protecting the Right to Be Forgotten for the Outsourced Plain Images

This article describes how cloud storage dramatically benefits people in freeing up their local storage space, while bringing the separation of the data ownership and private manipulation. Hence, it is difficult for the cloud user to make sure that the cloud storage provider (CSP) has obeyed the request of deletion to remove all corresponding data. To solve the issue technically, this article proposes an interactive cloud-user watermarking protocol (CUW) based on the homomorphic encryption. To meet security requirements, the encrypted watermark is embedded into encrypted data. Moreover, to enjoy the convenient cloud services, the uploaded data is eventually stored in the cloud server in the form of plain text. The performance of the CUW protocol is evaluated through a prototype implementation.