The communications industry has a new, forward‐thinking architecture: software‐defined networks (SDN). The inflexible structure of conventional networks severely hinders their ability to service modern organizations. The increased adaptability and transparency of SDN‐powered networks makes them more vulnerable to security hazards like Distributed denial of service (DDoS) assaults. The switch information system introduces protection at the cost of some degree of adaptability. The information and software layers are potential entry points for DDoS assaults. The flow‐based policies frequently collide at the application layer, giving rise to safety issues. The central nervous system of the network's components is the SDN controller located at the control layer. The centrally located controller interacts with networking hardware via switches. Attacks on control devices, switches, and communication channels can cause vulnerabilities in SDN networks. The study proposes Blockchain‐SDN‐based switch information security (BC‐SDN‐SIS) to address the information security problems. SDN applications operate at the highest level of SDN controllers, facilitating the easy rollout of new network services. The suggested design uses a distributed BC approach to guarantee confidentiality, anonymity, privacy, and scalability. The proposed BC‐SDN‐SIS model increases the accuracy ratio of 97.45%, precision ratio of 98.43, recall ratio of 97.34, effectiveness ratio of 97.6%, bandwidth of 2.5 Mbps, latency rate of .04 ms and F1‐score ratio of 98.28% compared to other existing models.