Blockchain and Smart Contracts for Digital Copyright Protection

In a global context characterized by a pressing need to find a solution to the problem of digital copyright protection, buyer-seller watermarking protocols based on asymmetric fingerprinting and adopting a “buyer-friendly” approach have proven effective in addressing such a problem. They can ensure high levels of usability and security. However, they usually resort to trusted third parties (TTPs) to guarantee the protection process, and this is often perceived as a relevant drawback since TTPs may cause conspiracy or collusion problems, besides the fact that they are generally considered as some sort of “big brother”. This paper presents a buyer-seller watermarking protocol that can achieve the right compromise between usability and security without employing a TTP. The protocol is built around previous experiences conducted in the field of protocols based on the buyer-friendly approach. Its peculiarity consists of exploiting smart contracts executed within a blockchain to implement preset and immutable rules that run automatically under specific conditions without control from some kind of central authority. The result is a simple, usable, and secure watermarking protocol able to do without TTPs.