Trust as Infrastructure: Purple Teams and the Evolution of Smart Cities • Whitney Pettrey

Smart cities are more than technological marvels; they are ecosystems of trust. Every interaction—whether it’s a commuter relying on an autonomous train, a doctor accessing patient records through integrated networks, or a citizen engaging with city services—relies on an unspoken assurance: the systems underpinning daily life are secure, reliable, and resilient.

Yet trust is fragile. The very connectivity that fuels urban innovation also amplifies the risk of cascading failures, data breaches, and critical infrastructure disruptions. This fragility poses a profound question: who ensures that the invisible scaffolding of our digital metropolises is not just functional, but inviolable?

Purple Teams have traditionally bridged offensive and defensive cybersecurity practices, but their role is evolving. As the architects of trust in smart cities, they are no longer confined to securing systems—they are tasked with safeguarding the confidence citizens place in the urban technologies that define modern life. This emerging responsibility reshapes urban security strategies, fosters collaboration across diverse stakeholders, and positions Purple Teams as central figures in shaping a future where innovation and confidence coexist seamlessly.

Trust as the Foundation of Smart Cities

In the interconnected world of smart cities, trust is not a luxury—it is an essential currency. It fuels every interaction and decision, from the commuter who relies on an autonomous transit system to the entrepreneur who invests in digitally connected infrastructure. Trust transforms urban innovation from a concept into a lived reality, where citizens, businesses, and governments can engage with confidence. Without it, the intricate systems of a smart city unravel into inefficiency, hesitation, and fragmentation.

Unlike traditional cities, where physical infrastructure serves as the bedrock of trust, smart cities rely on digital ecosystems to maintain their integrity. These systems must do more than function—they must reassure. Trust in smart cities transcends technical reliability; it is a shared belief in the resilience, security, and transparency of the technologies that underpin urban life. It is the invisible force that turns connectivity into community and progress into possibility.

Purple Teams stand at the heart of this dynamic, ensuring that trust is not merely preserved but deliberately cultivated. Their work integrates resilience into the very architecture of urban systems, transforming trust from an intangible ideal into a tangible reality. By embedding transparency, fostering collaboration, and anticipating vulnerabilities, Purple Teams establish a foundation where technology and confidence evolve together.

The result is a city where digital systems are more than tools—they become conduits of trust, enabling seamless interactions between citizens, businesses, and governments. It is within this framework that Purple Teams begin to translate trust into action, reshaping urban ecosystems and redefining resilience.

The Evolving Role of Purple Teams in Smart Cities

The promise of smart cities is not merely technological; it is human. It is the promise of systems that work seamlessly to empower communities, protect privacy, and enable innovation. But this promise exists alongside profound complexity. With every connection forged between critical infrastructure, IoT devices, and public services, the attack surface expands—and so too does the need for those capable of safeguarding it.

Purple Teams, once confined to uniting the offensive expertise of Red Teams and the defensive strategies of Blue Teams, now stand at the crossroads of security and trust. In the dynamic ecosystems of smart cities, their role has evolved into something far more significant. They are not just protectors of systems but stewards of confidence, navigating a world where cybersecurity is as much about people as it is about technology.

Building Trust Through Transparency

In an interconnected world, trust is fragile but indispensable. It is the foundation upon which communities embrace innovation and rely on the systems that underpin daily life. Purple Teams, as architects of this trust, go beyond technical fixes to create a culture of transparency and shared understanding:

Demystifying Complexity: By offering accessible public briefings and explaining resilience strategies in plain terms, Purple Teams empower stakeholders—from policymakers to citizens—to engage with urban security with clarity and confidence.
Transforming Crisis Communication: When incidents occur, Purple Teams bring order to chaos through real-time updates and clear resolution strategies, ensuring that uncertainty is replaced by reassurance.
Cultivating Shared Ownership: Through open collaboration with city leaders, businesses, and community organizations, they foster a sense of collective responsibility for the security of shared spaces and systems.

Reframing Security as Citizen-Centric

The true measure of a smart city is its ability to enhance the lives of its people. Purple Teams understand this and work to ensure that security frameworks serve citizens first, addressing not just technical vulnerabilities but also human concerns:

Protecting Privacy as a Priority: Safeguarding personal data against misuse or breach builds a foundation of trust that citizens can rely on when engaging with city services.
Securing Critical Services: From healthcare to energy grids, Purple Teams ensure that essential infrastructures remain uninterrupted, especially during crises, maintaining the public’s trust in the city’s capacity to deliver.
Advocating for Empowerment Through Security: They integrate security measures into innovations in ways that enhance usability and accessibility, making advanced technologies feel safe and empowering, rather than intrusive.

Proactive Incident Response as a Catalyst for Confidence

In the high-stakes environment of smart cities, every moment during a cyber incident matters. The ability to respond effectively can strengthen public confidence or risk its erosion. Purple Teams approach these moments not as challenges but as opportunities:

Turning Crises Into Confidence-Building Moments: Through decisive and transparent action, Purple Teams neutralize threats while demonstrating the city’s resilience.
Engaging Stakeholders in Real Time: By involving key players—government officials, private sector leaders, and citizen representatives—in resolution efforts, Purple Teams reinforce a shared commitment to security and trust.

Bridging Sectors for Unified Resilience

Smart cities are not governed by a single entity; they are a mosaic of public agencies, private enterprises, and civic organizations. This fragmentation poses a challenge that Purple Teams are uniquely equipped to address:

Uniting Disparate Efforts: Acting as the connective tissue between stakeholders, Purple Teams align diverse priorities into a cohesive, city-wide strategy.
Facilitating Cross-Sector Collaboration: They leverage intelligence-sharing frameworks to anticipate threats and deploy unified defenses, creating a network of resilience that transcends individual organizations.

As Purple Teams expand their role, their work becomes indispensable—but also more complex. These evolving responsibilities lead to an essential question: who are Purple Teams, and how are they formed? Exploring their origins, structure, and governance reveals the deliberate strategy and investment required to sustain their critical contributions to smart city ecosystems.

Who Are Purple Teams, and Where Do They Come From?

Purple Teams do not arise spontaneously; they are forged through deliberate strategy, sustained collaboration, and intentional investment. In the context of smart cities, they stand as a critical response to the growing complexity of urban ecosystems. As the convergence point for the offensive acumen of Red Teams and the defensive vigilance of Blue Teams, Purple Teams embody an operational philosophy that transcends traditional boundaries. They are not merely technologists but architects of resilience, ensuring that smart cities remain secure, adaptive, and trusted.

The formation of Purple Teams reflects the unique needs of each smart city ecosystem. Their existence is shaped by the interplay of public and private interests, regulatory frameworks, and the imperative for cross-sector collaboration. Yet, their mission remains consistent: to bridge gaps, align priorities, and fortify the trust that underpins modern urban life.

A Collective of Experts or a Defined Entity?

The identity and structure of Purple Teams vary widely, but their shared purpose is clear—to address vulnerabilities and align cybersecurity strategies in increasingly interconnected urban environments. Depending on the city’s resources and cybersecurity maturity, Purple Teams take on distinct forms:

Internal Teams: Embedded within large organizations or government agencies, internal Purple Teams operate as dedicated, in-house units tasked with protecting critical infrastructure. They are often deeply integrated into cybersecurity departments, working under direct accountability to city administrators or sector-specific leadership.
External Collaboratives: For cities without the capacity to build internal teams, Purple Teams can be sourced from private cybersecurity firms. These external teams provide specialized expertise, offering tailored strategies to meet the evolving demands of smart city infrastructure.
Distributed Collectives: In many cases, Purple Teams operate as multi-sector coalitions, drawing on the expertise of public, private, and nonprofit stakeholders. Frameworks like Information Sharing and Analysis Centers (ISACs) or initiatives such as the Capitol Cyber Initiative (CCI) exemplify this approach, pooling resources and intelligence to secure shared systems.

Public, Private, or Hybrid Responsibility?

No single entity can shoulder the full burden of forming and sustaining Purple Teams. The responsibility is inherently shared, reflecting the interconnected nature of smart city infrastructure:

Public Sector Leadership: Governments often lead the charge, particularly in securing critical infrastructure tied to public safety, utilities, and national security. Public sector-driven Purple Teams provide the oversight and accountability necessary to align cybersecurity efforts with regulatory frameworks and societal priorities.
Private Sector Innovation: Technology companies, as the innovators driving advancements in IoT, AI, and cloud infrastructure, frequently establish their own Purple Teams. These teams ensure the integrity of proprietary systems, safeguarding the foundational technologies upon which smart cities depend.
Hybrid Models: The most impactful Purple Teams operate within hybrid frameworks, where public and private entities collaborate to align resources, intelligence, and strategic goals. These partnerships amplify the strengths of each sector, fostering a collective defense that is both scalable and adaptive.

Governance and Oversight: Aligning Purpose and Action

For Purple Teams to thrive, they must operate within a framework of clear governance. Governance transforms tactical expertise into strategic impact, ensuring alignment with broader urban goals:

Defining Strategic Objectives: Governance begins with a clearly articulated mandate, ensuring that Purple Teams prioritize the security challenges most critical to the city’s operations and resilience.
Establishing Accountability Mechanisms: Clear reporting structures—whether to government bodies, corporate leadership, or multi-sector oversight boards—are essential for maintaining focus, transparency, and effectiveness.
Facilitating Regular Communication: Governance frameworks must prioritize open channels of communication between Purple Teams and their stakeholders, fostering trust and enabling coordinated responses to emerging threats.

Building Purple Teams: A Deliberate and Collaborative Effort

The creation of Purple Teams requires more than technical expertise; it demands foresight, investment, and cultural alignment. Successful Purple Teams are built on three foundational pillars:

Advanced Training and Expertise: Purple Teams require individuals with deep knowledge of both offensive and defensive cybersecurity methodologies, coupled with the agility to address the unique challenges of smart city environments.
Sustained Resource Commitment: Adequate funding, technology, and support infrastructure are essential to ensure operational effectiveness and longevity.
Fostering a Culture of Collaboration: Purple Teams thrive in environments that prioritize curiosity, innovation, and cross-disciplinary collaboration. This cultural alignment is particularly crucial in hybrid models, where diverse stakeholders must work together seamlessly.

As Purple Teams evolve within the framework of smart cities, their impact extends far beyond their structural origins. Their day-to-day responsibilities reveal the depth of their influence, as they safeguard vulnerabilities, strengthen resilience, and actively foster trust. Understanding these tangible contributions offers a window into how Purple Teams redefine security in urban environments, setting the stage for their critical role in enabling smart city innovation.

What Do Purple Teams Do in Smart Cities?

In the intricate ecosystems of smart cities, where technology is inseparable from the daily lives of citizens, Purple Teams operate at the nexus of innovation and security. Their role goes far beyond uniting the offensive insights of Red Teams and the defensive strategies of Blue Teams. Instead, they take on a multifaceted responsibility: navigating the complexities of interconnected systems, mitigating vulnerabilities, and safeguarding the trust that underpins urban life.

Smart cities face unique challenges—interconnected systems such as IoT networks managing transportation or SCADA systems regulating energy grids create extraordinary opportunities for efficiency but also expose critical vulnerabilities. Purple Teams address these challenges with precision and foresight, ensuring that urban frameworks are resilient against threats while remaining adaptive to the needs of their communities. Their work spans six critical domains, each essential to securing the technological and societal foundations of smart cities.

Identifying and Mitigating Vulnerabilities

Smart cities rely on an intricate web of systems, where even minor vulnerabilities can cascade into major disruptions. Purple Teams:

Simulate Advanced Threats: By emulating tactics used by adversaries such as ransomware gangs, nation-state actors, and hacktivist groups, Purple Teams expose weak points in urban systems, enabling targeted improvements.
Develop Tailored Defenses: Through close collaboration with Blue Teams, they translate their findings into customized strategies that address specific vulnerabilities, ensuring that critical systems remain secure and reliable.

Proactive Incident Response

When breaches or failures occur, the ability to respond effectively can define a city’s resilience. Purple Teams:

Act as First Responders: They lead the charge during cyber incidents, coordinating swift and strategic responses to neutralize threats and minimize downtime for essential services like emergency response and public transportation.
Enable Adaptive Recovery: By analyzing attack vectors in real time, Purple Teams evolve defensive measures, preventing similar incidents in the future and reinforcing long-term resilience.

Facilitating Collaboration and Intelligence Sharing

No single entity can secure a smart city alone. Purple Teams:

Bridge Organizational Gaps: By acting as intermediaries, they foster collaboration among public agencies, private enterprises, and third-party vendors, ensuring a unified approach to cybersecurity.
Leverage Global Threat Intelligence: Utilizing networks like ISACs, they anticipate and address emerging risks, creating a shared shield against evolving threats.

Enhancing Public Trust Through Transparency

Trust is the lifeblood of a smart city. Purple Teams:

Engage in Public Communication: They demystify cybersecurity efforts, providing stakeholders with clear and actionable updates that build confidence in the city’s digital infrastructure.
Educate Stakeholders: From city officials to citizens, Purple Teams empower individuals through training and workshops, fostering a culture of shared responsibility for security.

Embedding Security in Urban Innovation

As cities innovate, Purple Teams ensure that security is not an afterthought but a core element of progress. They:

Secure Emerging Technologies: Purple Teams work alongside technologists and urban planners to integrate robust security protocols into AI systems, IoT devices, and 5G networks from the outset.
Strengthen Legacy Infrastructure: Recognizing that older systems remain vital to urban operations, they address vulnerabilities in these technologies, ensuring seamless and secure integration with modern innovations.

Conducting Continuous Testing and Optimization

The cybersecurity landscape is ever-changing, requiring perpetual vigilance. Purple Teams:

Perform Regular Penetration Testing: By simulating real-world attack scenarios, they uncover and address weaknesses, ensuring defenses remain effective and up-to-date.
Iterate on Defensive Strategies: Purple Teams analyze the performance of implemented measures, refining them to stay ahead of adversaries and adapting to the evolving needs of urban environments.

As Purple Teams execute their responsibilities, their impact transcends system defense—they redefine urban security itself. Resilience shifts from a reactive safeguard to a proactive design principle, embedded into the core of smart cities. This transformation creates urban environments that are not just innovative but inherently secure, where every technological advance is fortified against potential threats.

By embedding security into every layer of a city’s infrastructure—from legacy systems to cutting-edge innovations—Purple Teams establish a new paradigm of resilience. Security becomes more than protection; it is the foundation of trust and progress in an increasingly interconnected world.

Architects of a New Paradigm: Security as a Design Principle

The evolution of smart cities represents more than technological advancement—it is a transformation of how urban systems serve society. In this reimagining, security must not remain an afterthought, layered onto existing frameworks or addressed reactively. It must be integral, shaping the very structure of cities from the earliest stages of planning to the deployment of cutting-edge technologies. This shift demands a new approach, one defined by foresight, collaboration, and precision—qualities that define the work of Purple Teams.

Purple Teams lead this paradigm shift, ensuring resilience is not reactive but inherent, woven into the systems that power modern cities. Their influence extends beyond technical safeguards to rethinking how cities are designed to anticipate risks, adapt to challenges, and inspire confidence. Whether modernizing legacy systems or pioneering next-generation innovations, Purple Teams redefine what it means to create cities that are both secure and forward-looking.

Proactive Security for Dynamic Ecosystems

Smart cities are constantly evolving, shaped by technological innovation, societal demands, and emerging threats. The ability to navigate this complexity and adapt to new challenges is fundamental to their success. Purple Teams ensure cities remain agile and resilient by:

Anticipating Vulnerabilities During Development: Identifying potential risks early in the design process, addressing weaknesses before they become critical.
Ensuring Systems Evolve with Threats: Creating adaptive security measures that align with the shifting tactics of adversaries, keeping urban systems ahead of evolving challenges.

Shaping Policy and Governance

Security is not merely a technical concern—it is a strategic imperative for governance and urban planning. Purple Teams bring their expertise to the policy table, influencing decisions that shape the future of cities:

Advancing Resilience-Driven Policies: Guiding public and private sector leaders in prioritizing security within legislative frameworks and long-term planning.
Equipping Decision-Makers with Knowledge: Providing urban planners and policymakers with the insights and tools needed to design systems that are not only innovative but durable against emerging threats.

Bridging Legacy Systems and Modern Innovations

Smart cities are defined by the coexistence of cutting-edge technologies and critical legacy systems, many of which were not designed for today’s interconnected landscape. Purple Teams ensure these systems do not become liabilities by:

Fortifying Older Infrastructure: Strengthening legacy systems to meet modern security standards while maintaining their essential functions.
Seamlessly Integrating New Technologies: Creating solutions that allow advanced systems to operate cohesively with existing infrastructure, closing gaps that could otherwise be exploited.

This philosophy of building security into the essence of urban systems does more than safeguard technology—it fosters societal trust. When citizens, businesses, and governments can rely on their cities to be both innovative and secure, confidence grows. That confidence is not just a byproduct of smart cities; it is their foundation, enabling communities to thrive in an interconnected world.

Societal Trust: The True Measure of Smart City Success

The ultimate success of a smart city is not a measure of its technological sophistication but of its ability to earn and sustain the trust of its citizens. While cities may boast advanced AI-driven infrastructure, IoT-powered networks, and seamless digital services, these innovations are only as impactful as the confidence they inspire. Trust is the invisible thread connecting urban systems to their users—a guarantee of reliability, security, and resilience in the face of uncertainty.

Purple Teams are the architects of this trust. Their work extends beyond identifying vulnerabilities or strengthening defenses; they are the orchestrators of confidence, ensuring that citizens, businesses, and governments alike feel secure in engaging with smart city ecosystems. Whether safeguarding autonomous transportation systems or protecting healthcare data from cyber threats, Purple Teams ensure that trust becomes the cornerstone of innovation, enabling communities to embrace progress without hesitation.

This trust, however, is not a static achievement. It must be cultivated through deliberate action, cross-sector collaboration, and a commitment to transparency. Purple Teams are uniquely positioned to drive this transformation, but they cannot operate in isolation. The stakeholders who shape smart cities—public officials, private enterprises, and community leaders—must come together to empower these teams and align their efforts toward a shared vision of resilience and confidence.

Conclusion: Securing the Future Through Collaboration and Action

Smart cities embody the promise of a connected future, where technology enhances quality of life and communities thrive in harmony with innovation. But with great connectivity comes great responsibility. The role of Purple Teams as architects of trust underscores a critical truth: the success of smart cities depends on our collective ability to secure them—not just technically, but societally.

This is a call to action for policymakers, industry leaders, and community advocates:

For Policymakers: Create policies that incentivize collaboration between public and private sectors, establish frameworks for secure-by-design urban planning, and prioritize investments in cybersecurity talent and resources. Your decisions will shape the foundation of smart city security.
For Public-Private Partnerships: Embrace hybrid models where Purple Teams can flourish as unified forces, pooling expertise from government agencies, private firms, and information-sharing alliances like ISACs. Collaboration is not optional; it is the only way to address the scale and complexity of urban cybersecurity challenges.
For Community Leaders: Advocate for transparency and citizen education as integral components of trust-building. Empower citizens to understand and engage with cybersecurity efforts, ensuring that smart city innovations are met with confidence rather than skepticism.

The responsibility to secure smart cities is shared, but the vision must be clear. Purple Teams are not just defenders of infrastructure; they are catalysts for societal confidence, ensuring that urban systems work seamlessly, safely, and resiliently. By uniting behind this vision, we can transform smart cities from conceptual marvels into thriving, secure communities that inspire trust at every level.

Through this commitment, the promise of smart cities is no longer an aspiration but an achievable reality. As technology and society evolve together, Purple Teams stand as the stewards of progress, ensuring that innovation remains a force for good. Trust, when built deliberately and safeguarded vigilantly, becomes the engine driving a future where citizens, businesses, and governments can confidently shape what comes next.

This is the future of smart cities—not just connected but trusted, not just innovative but resilient. And it is a future we must build together.