Blockchain-Based Trustworthy O2O Interaction in the Next 6G Ecosystem

In traditional mobile networks', trust between sub-scribers and their serving networks is based on a hardware root-of-trust: the SIM. Trust between service and home networks, when different, was based on Trusted Third Parties (TTPs), called Clearing Houses (CHs), which guarantee the trustworthiness of the evidence about service use. The $6\mathrm{G}$ scenario will see the number of subscribers boosted by mass deployment of Internet-of-Everything as well as the improvement of the network performance. At the same time, the performance required to the TTP to manage $6\mathrm{G}$ operator-to-operator $(\mathrm{O}2\mathrm{O})$ trustworthy interactions must be aligned to the $6\mathrm{G}$ ecosystem requirements as well. However, supporting scalability in $6\mathrm{G}\mathrm{O}2\mathrm{O}$ trust is still considered an open challenge. The aim of this paper is to tackle this challenge by presenting a blockchain-based approach for CHs, able to support $\mathrm{O}2\mathrm{O}$ trustworthy interactions in the $6\mathrm{G}$ scenario. Both home and roaming use cases are considered.