Organisations worldwide continue to depend on legacy Public Key Infrastructure (PKI) systems that were implemented when IT environments were far less complex. Traditional solutions, including Microsoft Active Directory Certificate Services (AD CS), were primarily designed to support internal networks and applications. Today, organisations must manage certificates across cloud platforms, connected devices and a rapidly growing number of machine identities.
PKI modernisation is critical today, given the central role it plays in securing digital communications, authenticating identities and protecting sensitive information. PKI modernisation involves upgrading existing infrastructure to meet changing security and operational requirements. It does not necessarily mean replacing every legacy system.
Instead, the objective is to introduce greater flexibility, automation and control over how digital certificates are issued, managed and maintained.
This article examines five important reasons to modernise PKI infrastructure and the common warning signs that suggest an organisation's existing approach may no longer be adequate.
Before considering the benefits of modernisation, organisations should assess whether their current PKI environment can support their evolving security requirements. Several common challenges indicate that existing infrastructure may be reaching its limits.
Many PKI environments were originally established to support a limited number of internal applications. Over time, these systems have been extended to accommodate additional users, devices, applications and business processes. The problem is that older PKI architectures were not necessarily designed for this level of expansion.
Legacy certificate authority (CA) systems may offer limited integration with modern security tools. They require significant manual administration and become increasingly difficult to maintain as configurations evolve. Some root CA certificates remain valid for decades. During that period, the technologies, security standards and operational requirements surrounding them can change considerably.
Without regular assessment and upgrades, organisations risk relying on infrastructure that no longer reflects their current security needs.
When centralised PKI services cannot respond quickly enough to business requirements, individual departments may implement their own certificate authorities or certificate management processes. This often happens without sufficient coordination with IT or security teams. The resulting environment can contain certificates that are poorly documented, inconsistently configured or entirely absent from central inventories.
Such fragmentation makes it harder to enforce security policies, identify certificate vulnerabilities and prevent unexpected service disruptions. Limited resources can make the problem worse, as teams prioritise immediate operational requirements over long-term certificate governance.
PKI management requires specialist knowledge, particularly when organisations operate multiple certificate authorities across different environments. However, responsibility for PKI is often distributed between infrastructure, networking, development and security teams. Without clearly defined ownership, important activities such as certificate renewal, policy enforcement, infrastructure maintenance and CA decommissioning may receive insufficient attention.
The long operational lifespan of PKI infrastructure adds another challenge. Organisations must retain the knowledge and processes required to manage systems that may remain in use for many years.
Establishing clear accountability is therefore an essential part of maintaining a secure and reliable PKI environment.
Modern organisations rarely operate within a single IT environment. Business applications and workloads may be distributed across on-premises infrastructure and multiple public cloud providers.
Traditional PKI architectures, particularly those built around fixed on-premises deployments, can struggle to support these arrangements efficiently. Modern PKI solutions provide deployment options that can be adapted to an organisation's infrastructure and security requirements.
Depending on operational needs, organisations can choose from cloud-hosted PKI, PKI as a Service (PKIaaS), on-premises solutions or hybrid deployments that combine multiple approaches. This flexibility becomes particularly valuable during major infrastructure changes.
For example, organisations operating across multiple jurisdictions may require distinct CA environments to accommodate different regulatory obligations or internal security policies. Modern PKI architectures make it easier to address these requirements without maintaining entirely disconnected systems.
Modern use cases introduce requirements that many older PKI deployments were not designed to accommodate.
For example, Internet of Things (IoT) environments may contain thousands or millions of connected devices requiring secure authentication. DevOps teams need certificate issuance and renewal processes that integrate directly into development pipelines. Cloud-native applications and containerised workloads may depend on short-lived certificates that are generated and rotated automatically.
Supporting these environments requires PKI infrastructure that can operate at scale and integrate with modern technologies.
A modern PKI platform should support established certificate management protocols, including:
REST APIs are equally important, allowing development and infrastructure teams to incorporate certificate management into existing applications and automated workflows. Legacy PKI solutions may support only a limited selection of these capabilities or require manual processes that slow down deployment. Modernisation allows organisations to introduce the necessary integrations and automation without compromising established security controls.
Importantly, this transition does not always require an immediate replacement of existing infrastructure. Modern PKI services can often operate alongside legacy certificate authorities, allowing organisations to migrate individual applications and workloads gradually. This phased approach reduces operational disruption and gives security teams greater control over the modernisation process.
Certificate requirements can increase rapidly as organisations expand their digital operations. Traditional PKI environments can become difficult to scale when their underlying architecture depends on separately managed certificate authorities and supporting servers.
For example, Microsoft AD CS commonly relies on individual CA instances hosted on Windows servers. Scaling such environments across multiple business units or locations can introduce additional administrative complexity, particularly where high availability and centralised governance are required.
Modern PKI platforms are designed to accommodate much larger certificate volumes while reducing the infrastructure needed to manage them. This is particularly important for businesses operating extensive IoT networks or cloud-native environments where certificate demand can change quickly.
Scalability also has direct implications for operational costs. Maintaining numerous legacy PKI systems can require significant expenditure on infrastructure, licensing, administration and specialist personnel. Consolidating these systems onto a modern platform can reduce duplication and simplify ongoing maintenance. A scalable PKI architecture helps organisations accommodate future growth without continually expanding the complexity of their security infrastructure.
Over time, enterprise PKI environments often become fragmented. Different departments may adopt separate certificate authorities to support specific applications, devices or operational requirements. While these decisions may address immediate needs, they can eventually create a complicated infrastructure with inconsistent security policies and limited central oversight.
Keyfactor research has previously highlighted that large enterprises may operate nine or more separate PKI infrastructures. Managing multiple environments introduces additional costs and makes it harder to maintain consistent security standards.
PKI modernisation provides an opportunity to consolidate certificate authority management and establish more effective governance.
Some enterprises support this approach by establishing a Cryptographic Centre of Excellence (CCoE). A CCoE typically brings together representatives from security, infrastructure, architecture and other relevant business functions.
This team sets encryption standards and establishes certificate policies. It also evaluates new technologies and keeps the organisation aligned with evolving security needs. Modern PKI platforms can support these activities by providing centralised administration, reporting and policy enforcement.
However, technology alone is not sufficient. Organisations must also define ownership, document certificate management procedures and ensure that governance arrangements remain effective as infrastructure changes.
A consolidated PKI environment, supported by clear responsibilities and consistent policies, can significantly reduce administrative complexity and strengthen overall security management.
Manual certificate management is becoming increasingly difficult to sustain. Organisations may be responsible for thousands of certificates distributed across applications, servers, devices and cloud environments.
Tracking expiry dates and renewals creates unnecessary operational risk. An expired certificate can interrupt critical services, and prevent applications from communicating. Incorrectly configured or poorly managed certificates may also introduce security vulnerabilities and compliance concerns.
Certificate lifecycle automation is therefore one of the most important benefits of PKI modernisation. Modern solutions can automate essential activities. They can also provide centralised visibility across certificates issued by different certificate authorities. This reduces reliance on manual intervention and helps security teams identify potential issues before they affect business services. Beyond automation, organisations must also consider their ability to adapt to changing cryptographic requirements. This capability is commonly referred to as crypto-agility.
Crypto-agility enables organisations to introduce new cryptographic algorithms, update certificate policies and transition between technologies without rebuilding their entire security infrastructure. It is becoming particularly important as the industry prepares for post-quantum cryptography (PQC). Quantum computing presents a potential long-term threat to several widely used public-key cryptographic algorithms. Organisations will increasingly need to assess where vulnerable cryptographic algorithms are used and develop plans for adopting quantum-resistant alternatives.
Modern PKI infrastructure can make this transition more manageable. Preparing for these changes now can reduce the likelihood of expensive and disruptive migrations in the future.
Legacy PKI infrastructure can introduce unnecessary security and operational risks. However, PKI modernisation should not be viewed simply as an infrastructure upgrade. It is an opportunity to strengthen digital trust. It can help the organisation improve security governance and reduce operational risks associated with managing certificates across increasingly complex IT environments.
Organisations that modernise their PKI infrastructure proactively will be better positioned to support future technologies, maintain reliable services and respond to evolving cybersecurity requirements.
PKI modernisation involves upgrading or replacing outdated public key infrastructure to improve security, scalability, automation and integration with modern IT environments. It may include introducing new certificate management platforms, consolidating certificate authorities and automating certificate lifecycle processes.
Older PKI systems may lack the flexibility, scalability and automation required to support cloud applications, connected devices and modern development environments. Modernisation can improve certificate visibility, reduce administrative complexity, strengthen governance and minimise the risk of certificate-related service disruptions.
Yes. Many modern PKI solutions can operate alongside existing certificate authorities, allowing organisations to migrate applications and services in stages. A phased migration helps reduce disruption while giving teams time to validate integrations, update policies and establish new management processes.
PKI modernisation refers to the broader process of improving an organisation's certificate infrastructure and management capabilities. PKI as a Service (PKIaaS) is one possible deployment model in which a third-party provider hosts or manages PKI infrastructure. Organisations can modernise PKI through cloud-based, on-premises, hybrid or managed solutions.
Modern PKI platforms can improve crypto-agility by making it easier to update cryptographic algorithms, certificate configurations and related security policies. This flexibility helps organisations prepare for the adoption of post-quantum cryptographic standards without requiring a complete redesign of their infrastructure.
Important capabilities include flexible deployment models, support for protocols such as ACME, SCEP, EST and CMP, API integrations, automated certificate lifecycle management, centralised governance and high availability. Organisations should also assess scalability, crypto-agility and alignment with relevant security and compliance requirements, including ISO 27001.
The timeline depends on the size and complexity of the existing PKI environment. Smaller implementations or initial cloud-based deployments may be completed within weeks, while enterprise-wide migrations involving multiple certificate authorities and applications can take several months or longer. A phased approach allows organisations to prioritise critical systems and reduce operational risk.
Costs vary according to certificate volumes, deployment models, integration requirements and the complexity of existing infrastructure. Although modernisation may involve upfront investment, automation and consolidation can reduce long-term infrastructure and administration costs. Organisations should evaluate the total cost of ownership rather than focusing solely on initial implementation expenses.