TeraFlow will create a new type of secure cloud-native SDN controller that will radically advance the state-of-the-art in beyond 5G networks. This new SDN controller shall be able to integrate with the current NFV and MEC frameworks as well as to provide revolutionary features for both flow management (service layer) and optical/microwave network equipment integration (infrastructure layer), while incorporating security using Machine Learning (ML) and forensic evidence for multi-tenancy based on Distributed Ledgers. The target pool of stakeholders expands beyond the traditional telecom operators towards edge and hyperscale cloud providers. These actors will be benefited from TeraFlow by a) exploiting a new type of secure SDN controller based on cloud-native solutions while, b) achieving substantial business agility with novel and highly dynamic network services with zero-touch automation features. The novel TeraFlow architecture will be validated through the implementation of the TeraFlow OS with the following innovations: a) Cloud-Native Architecture; b) Transport Network Integration; c) Unification of Network and Cloud Resource Management; d) ML-based security; and e) Distributed Ledger Technologies. The final demonstrations (TRL 5) will support three use cases: Autonomous Networks Beyond 5G, Automotive, and Cybersecurity. During the course of the TeraFlow project (30 months), experimental implementation and demonstration of prototypes will also play an important role in the project, including communication and dissemination activities and strong collaboration with Standard Defining Organizations (ETSI NFV, ZSM, ENI, PDL, IETF, ONF), and open source software community with dedicated focus on ONF ONOS and ETSI OpenSourceMANO. TeraFlow will also foster strong relationship with other 5GPPP projects through multiple collaboration activities. A concrete plan for TeraFlow results adoption will be implemented as well.