The Internet of Things (IoT) enables increased connectivity between devices; however, this benefit also intrinsically increases cybersecurity risks as cyber attackers are provided with expanded network access and additional digital targets. To address this issue, this paper presents a holistic digital and physical cybersecurity user authentication method based on the Blockchain Random Neural Network. The Blockchain Neural Network connects increasing neurons in a chain configuration providing an additional layer of resilience against Cybersecurity attacks in the IoT. The proposed user access authentication covers holistically its digital access through the seven OSI layers and its physical user identity such as passport before the user is accepted in the IoT network. The user’s identity is kept secret codified in the neural weights, although in case of cybersecurity breach, its physical identity can be mined and the attacker identified, therefore enabling a safe decentralized confidentiality. The validation results show that the addition of the Blockchain Neural Network provides a user access control algorithm with increased cybersecurity resilience and decentralized user access and connectivity.