Editorial: Secure blockchain applications for smart cities: enhancing trust, privacy, and resilience

Smart cities aim to make urban life more efficient, inclusive, and sustainable by connecting public services across areas such as governance, mobility, energy, education, and commerce. This growing connectivity also concentrates risk. Citizens often need to share personal data many times across systems that do not communicate well with one another, and the failure of a single central authority can affect an entire service. In this setting, trust, privacy, and resilience become essential foundations for any secure urban digital infrastructure.

Blockchain and distributed ledger technologies offer promising responses to these challenges. By distributing control, making records verifiable, and keeping them tamper-resistant, these technologies can reduce the dependence on single points of trust, give people more control over their own data, and help services remain reliable even under pressure. Moving from promise to practice, however, still depends on questions of governance, usability, interoperability, regulation, and the incentives that shape adoption.

This Research Topic brought together original studies on how secure blockchain applications can strengthen trust, privacy, and resilience in smart cities. In particular, the four contributions address decentralised identity and digital citizenship, secure cooperation across institutional and national borders, and the economics of adoption. Together they show both the flexibility of these technologies and the conditions they need to become dependable public infrastructure. For clarity, we group the contributions into two themes.

Trust and privacy in identity and digital citizenship

“Towards a refined architecture for socio-technical decentralised identity services” (Hwang et al.): this study observes that most work on decentralised identity has focused mainly on technical aspects, giving less attention to governance, usability, and trust among the people and institutions involved. To address this gap, the authors propose a framework that brings together social factors, such as governance and user-centred design, with technical ones, such as privacy and interoperability. Building on this framework, they outline an identity service architecture suited to organisational use, aimed at reducing the practical barriers that often slow real adoption.

“CCDigital: Protection of Digital Citizenship folder based on DLT-Blockchain” (Ramirez Lopez et al.): this work addresses the burden citizens face when they must repeatedly prove the same documents across public institutions. The authors present a prototype that supports the issuing, authorisation, and verification of official documents while keeping sensitive content protected and recording verification events in a traceable way. Tested in a controlled setting inspired by digital citizenship services, the prototype demonstrates the core workflow and, just as importantly, identifies the governance, usability, security, and scalability questions that must be resolved before such systems can be used in real public services.

Secure cooperation and adoption incentives

3. “ZkHybridChain: ultra-efficient cross-border credit recognition” (Xu et al.): recognising academic achievements across countries is often slowed by fragmented records, differing regulations, and limited efficiency. The authors propose an approach that combines public and private components so that credentials can be verified without exposing sensitive information, helping to reconcile privacy, regulatory compliance, and performance. The result points to a more scalable and privacy-aware way to support trust in international education.

4. “Blockchain adoption strategies under the framework of a dual-channel supply chain” (Chen and Li): moving from architecture to motivation, this study examines when participants in a supply chain choose to adopt blockchain. The authors show that this decision depends strongly on how much consumers care about privacy, and that different conditions lead to different outcomes for the companies involved. Their analysis is a useful reminder that adopting secure technologies in smart cities is not only a technical matter but also an economic and behavioural one.

Taken together, the four contributions connect naturally to the three pillars of this Research Topic. Trust appears as something built through social and technical design rather than guaranteed by technology alone, as the studies on identity and digital citizenship make clear. Privacy is treated as a goal that can be deliberately designed and even encouraged, whether by protecting information during verification or by recognising how privacy concerns shape the decision to adopt. Resilience runs through the shared move away from fragmented systems that depend on a single authority toward more distributed and verifiable approaches.

Just as notable is the candour of these studies about what remains to be done. Standardisation, alignment with regulation, interoperability across institutions, scalability under real demand, and independent security evaluation appear again and again as the distance between promising prototypes and dependable public infrastructure. Closing that distance defines a clear agenda for the next stage of research on secure blockchain for smart cities. We warmly thank all authors, reviewers, and readers who made this Research Topic possible, and we hope it encourages further collaboration across the fields of blockchain, security, privacy, and urban innovation.