What Is PKIaaS? A Complete Guide to PKI as a Service

The need for this model has never been more pressing. Digital certificates are proliferating across every corner of the enterprise, from cloud workloads and containers to IoT devices and remote endpoints. At the same time, certificate lifespans are shrinking, compliance requirements are tightening, and qualified PKI professionals remain in short supply. For many IT and security leaders, maintaining a secure, scalable PKI deployment in-house has become unsustainable.

This guide is designed for IT and security leaders evaluating PKIaaS as a delivery model. It covers how PKIaaS works, the core capabilities to look for, common use cases, and how to avoid the most common evaluation pitfalls. If you are looking for a foundational primer on PKI itself, that topic is covered separately in our deep-dive on PKI. This article focuses specifically on the “as a Service” model and what it means for your organization.

Why organizations are moving to PKIaaS

The growing complexity of enterprise PKI

PKI has been a core mechanism in enterprise security for over two decades, but the environments it protects have changed dramatically. The shift to containers, multi-cloud architectures, mobile endpoints, and IoT has multiplied both the number of PKI use cases and the volume of certificates organizations must manage. While on-premise PKI deployments are perfectly capable to scale and meet this demand, doing so manually has become unsustainable for most organizations lacking expertise, proper lifecycle automation and centralized visibility.

This is where agility becomes an important factor. Introducing a PKI deployment in the cloud, whether it is alongside existing on-premise infrastructure or as the primary issuance mechanism, add flexibility and redundancy that manual deployments struggle to provide. The organization stays in control of the certificate profiles, algorithms, validity periods, etc. making it an agility feature driven by policy, rather than just a decision to outsource the infrastructure.

Teams responsible for PKI often struggle with unclear ownership, competing priorities, and limited resources. In many organizations, PKI is managed by a small group (or even a single person) who balances it alongside other responsibilities. As certificate counts grow and use cases diversify, this model breaks down.

Staffing and expertise gaps

Only a small fraction of IT and security teams report having sufficient staff dedicated to PKI. The underlying trend is persistent: limited expertise, role fragmentation, and personnel turnover create ongoing operational risk. When a seasoned PKI professional leaves, the institutional knowledge they carry often leaves with them.

PKI skills are typically developed through years of hands-on experience and organic growth within an organization. They cannot easily be replaced through hiring or short-term training programs. This makes every personnel change a potential disruption to PKI operations and security posture.

Compelling events that trigger the switch

Organizations rarely move to PKIaaS on a whim. The decision is usually triggered by a specific event or converging pressures. Common catalysts include:

• Algorithm transitions, such as the migration from SHA-1 to SHA-2, and the approaching shift to post-quantum cryptography
• CRL outages that block critical services and expose fragile infrastructure
• CA renewal cycles that reveal gaps in documentation, processes, or staffing
• Mergers and acquisitions that introduce multiple, incompatible PKI environments
• New cloud or IoT initiatives that demand rapid certificate provisioning at scale
• Exponential certificate growth that overwhelms existing tooling and processes

Market momentum

The PKIaaS market is experiencing significant growth. Research from Frost & Sullivan confirms that PKIaaS adoption has accelerated substantially since 2022, with strong momentum expected to continue globally. North America remains the largest market, while Europe, Asia-Pacific, and the Middle East are seeing increasing uptake.

The global shortage of cybersecurity and PKI professionals is expected to persist, further driving demand for managed PKI services. Organizations that lack the internal resources to maintain complex PKI environments are increasingly looking to service providers to close the gap.

How PKIaaS works

The managed service model

PKIaaS follows a clear division of responsibilities between the provider and the customer. The lifecycle typically unfolds in four phases:

1. Build: The provider designs and constructs a dedicated offline root CA in a high-security facility, following best-practice PKI architecture.
2. Deploy: Highly available, HSM-backed issuing CAs are deployed by the provider in a dedicated cloud environment that is isolated from other customers and configured to the customer’s requirements.
3. Maintain: The provider handles ongoing infrastructure management around the clock, including firewalls, patching, CRL maintenance, and continuous monitoring.
4. Run: The customer’s teams handle day-to-day operations, including setting issuance policy, approving requests, and integrating the provider’s automation tooling for discovery and certificate lifecycle management.

In other words, the provider builds it, deploys it and maintains it, and the customer runs it. The provider owns the heavy lifting of infrastructure, reliability and security, while the customer retains operational control over their certificates and policies.

Key architectural components

A well-architected PKIaaS deployment includes several critical components:

• Offline root CA with HSM protection: The root CA is the trust anchor for the entire PKI hierarchy. It should be stored offline, air-gapped, and protected by dedicated hardware security modules (HSMs) compliant with FIPS 140-2 Level 2 or higher.
• Single-tenant cloud infrastructure: Each customer’s PKI should run in a dedicated environment with no shared infrastructure, ensuring isolation and security.
• Highly available issuing CAs: Online issuing CAs backed by HSMs, with separate application and database layers for scalability.
• Real-time revocation infrastructure: CRL and OCSP services that ensure revoked certificates are recognized immediately across the environment.
• Active Directory and autoenrollment integration: Seamless integration with enterprise directory services for automated certificate provisioning.
• Data backup and disaster recovery: Redundant systems and recovery procedures to protect against data loss or service interruption.

A critical architectural consideration is whether the provider builds all underlying PKI software in-house. Relying on third-party components introduces dependency risk. Providers that own their entire stack can deliver updates, patches, and cryptographic improvements faster and with greater confidence.

Integrated certificate lifecycle automation

PKIaaS and certificate lifecycle management (CLM) should be evaluated together, not as separate solutions. Issuing certificates is only the beginning. Organizations also need to discover existing certificates across the environment, receive expiration alerts, and generate centralized reports across multiple CAs and vendors.

A platform that combines PKIaaS and CLM into a single, cloud-based solution eliminates the need for disparate tools and reduces the operational complexity of managing certificates at scale. This integration becomes especially important as certificate volumes grow and lifespans shorten.

Core capabilities to look for in a PKIaaS solution

Offline root CA protection and key escrow

The root CA is the anchor of trust for your entire PKI hierarchy. Any compromise at the root level invalidates the entire chain. Leading PKIaaS providers protect root CAs in offline, air-gapped environments with dedicated HSMs stored in state-of-the-art physical security facilities (GSA Level 5 vaults, biometric access controls, 24/7 surveillance, and HD video monitoring).

Equally important is customer-controlled key escrow. You should retain full ownership of your root CA keys and recovery materials, with the ability to bring your PKI back in-house at any time. This eliminates vendor lock-in and ensures you always control your trust anchor.

Cloud infrastructure and high availability

PKIaaS infrastructure should be dedicated and single-tenant, with no shared components across customers. Key characteristics of a robust cloud deployment include SLA-driven uptime guarantees, unlimited scalability through separate application and database layers, HSMs for all online issuing CAs, and dedicated firewalls configured with least-privilege access policies.

High availability is not optional. When PKI services go down, the downstream impact can be immediate and wide-ranging, from blocked VPN connections and failed email signing to disrupted application authentication across the enterprise.

Security, compliance, and operations

Robust security and compliance practices are non-negotiable. Evaluate providers on whether they maintain SOC 2 Type II certification, publish and adhere to Certificate Policy and Certification Practice Statement (CP/CPS) frameworks, conduct regular PKI health checks, and deliver continuous service monitoring with SLA-driven incident response.

PKI is not a “set and forget” technology. Threats evolve, compliance requirements shift, and certificate volumes grow. A credible PKIaaS provider treats operations as an ongoing discipline, not a one-time deployment.

Implementation, delivery, and ongoing support

Modern PKIaaS solutions should deploy in weeks, not months. The speed of deployment is a meaningful differentiator, especially for organizations under pressure from compliance deadlines, M&A timelines, or emerging threats.

Beyond initial deployment, look for 24/7 support from dedicated PKI experts, continuous software updates, and a rolling product roadmap that demonstrates ongoing investment. Providers with deep hands-on consulting and deployment experience can anticipate challenges that less experienced vendors miss entirely.

Integration and extensibility

A PKIaaS platform should integrate seamlessly with the tools and protocols your teams already use. Look for support for standard protocols such as ACME, SCEP, EST, CMP, which enable enrollment, issuance and renewal. Look also for autoenrollment, along with REST APIs for custom integration of these protocols. Pre-built integrations with enterprise tools (HashiCorp Vault, Kubernetes, Active Directory, and DevOps platforms) reduce implementation time and operational friction.

Many of these integrations should be open-source and included at no additional cost. Evaluate whether the provider’s integration ecosystem is broad enough to support your current environment and flexible enough to accommodate future growth.

Common PKIaaS use cases

Enterprise IT and zero trust

PKI is a foundational component of zero trust architecture. It provides the identity layer for verifying users, devices, and workloads before granting access to resources. In hybrid environments that span on-premises data centers and multiple cloud providers, PKIaaS delivers the scalable, centrally managed certificate infrastructure that zero trust demands.

Multiple business units and functions rely on PKI availability, from network operations and endpoint security to application development and compliance. A managed service ensures that PKI infrastructure meets the reliability and performance requirements of the entire organization, not just a single team.

IoT and connected devices

Device manufacturers and industrial operators use PKIaaS to issue and manage certificates at scale across diverse connected device ecosystems. Use cases range from EV charging infrastructure and medical devices to smart meters, telecommunications equipment, and smart home products.

At IoT scale, manual certificate management is not viable. Automation and autoenrollment protocols become critical, enabling organizations to provision, renew, and revoke certificates across thousands or millions of devices without manual intervention.

DevOps and cloud-native environments

Cloud-native application development tools and architectures are driving new demand for PKI services. Development teams need to embed certificate issuance into CI/CD pipelines, secure containers and microservices, and manage ephemeral machine identities that may exist for only minutes or hours.

PKIaaS platforms that offer API-driven certificate issuance and integration with container orchestration tools (such as Kubernetes) enable development teams to consume PKI services without needing deep cryptographic expertise. This self-service model accelerates delivery while maintaining security standards.

Mergers, acquisitions, and PKI consolidation

Mergers and acquisitions often introduce multiple, incompatible PKI architectures that must be harmonized into a single, coherent environment. PKIaaS simplifies this consolidation by providing a managed platform that can maintain trust chains and compliance across complex multi-stakeholder environments.

M&A is the perfect opportunity to reassess your PKI strategy. Rather than absorbing legacy PKI infrastructure with all its technical debt, organizations can use a PKIaaS migration to establish a modern, best-practice PKI from the start.

PKIaaS vs. in-house PKI: making the right choice

Total cost of ownership considerations

When comparing PKIaaS to in-house PKI, the total cost of ownership extends well beyond software licensing. On-premises PKI requires investment in hardware (including HSMs), dedicated staff, ongoing compliance audits, disaster recovery infrastructure, and physical security for root CA materials. These costs are often distributed across budgets and underestimated.

PKIaaS consolidates these costs into a predictable subscription model. When evaluating pricing, look for scalable licensing that aligns with certificate count growth and provides a predictable cost structure. Per-certificate pricing models vary significantly across providers, so compare the total value delivered, not just the unit price.

When in-house PKI still makes sense

In-house PKI remains the right choice for some organizations. Highly customized environments, air-gapped networks with no cloud connectivity, or specific regulatory mandates may require a fully self-managed deployment. Also teams with vast PKI expertise and already existing infrastructure might be well prepared to deploy and run their own PKI. These scenarios are real, but organizations must be honest about whether any of these applies to them.

The best PKIaaS providers acknowledge this reality and offer deployment flexibility across on-premises, cloud, hybrid, and as-a-service models. This allows organizations to choose the delivery model that fits their requirements without being forced into a single approach.

The hybrid approach

Many organizations adopt a hybrid model that combines the best of both worlds. A strong PKIaaS platform can manage certificate lifecycles across hosted PKI, existing on-premises CAs, and public CA vendors from a single platform. This approach allows teams to modernize incrementally without a disruptive, all-or-nothing migration.

Hybrid deployments are increasingly common and represent a growing share of overall PKI adoption. They offer a practical path for organizations that need the scalability and expertise of a managed service but are not ready (or not required) to fully decommission their existing infrastructure.

What to avoid when evaluating PKIaaS providers

Giving up control of your root keys

Any vendor that does not give you the right to own your PKI should be ruled out immediately. Key escrow and the ability to bring your PKI back in-house are non-negotiable requirements. The provider should handle the design, deployment, and management of your PKI while you retain full control of root keys and recovery materials.

Vendor lock-in is a real risk in this market. If your provider does not offer clear contractual guarantees around key ownership and portability, it should be a disqualifying factor in your evaluation.

Shared, multi-tenant infrastructure

PKI should never be hosted on shared infrastructure. Multi-tenant environments introduce unnecessary risk and limit the flexibility to customize configurations to your specific requirements. Insist on dedicated, single-tenant environments where your PKI infrastructure is fully isolated from other customers.

A single-tenant solution offers more flexibility for configuration, compliance, and performance tuning. It also simplifies audit and compliance processes by eliminating ambiguity about data isolation and access controls.

Incomplete solutions without certificate management

PKIaaS without integrated certificate lifecycle management is fundamentally incomplete. As soon as you issue your first certificate, you have a certificate management need: tracking where it is deployed, when it expires, and whether it remains compliant with your policies.

Evaluate providers that combine both PKIaaS and CLM capabilities into a single platform. Running separate tools for certificate authority management and certificate lifecycle management creates unnecessary complexity, increases the risk of blind spots, and makes it harder to maintain a unified view of your certificate landscape.

How Keyfactor can help

Keyfactor’s PKI as a Service combines fully managed, cloud-based PKI with powerful certificate lifecycle automation in a single platform. Every deployment starts with a best-practice PKI built from the ground up, including an always-offline, air-gapped root CA protected by dedicated FIPS 140-2 Level 2 HSMs, a fully redundant CRL infrastructure and robust data recovery and backup services, all deployed in a single-tenant cloud environment. Customers retain full control of root keys and recovery materials, ensuring no vendor lock-in.

Key differentiators include:

• End-to-end PKI control: Keyfactor develops and maintains the entire PKI stack in-house, from the cryptographic libraries (Bouncy Castle) to the CA software (EJBCA), ensuring continuous improvements and long-term reliability.
• Unmatched expertise and scale: With over 20 years of PKI consulting and deployment experience, Keyfactor supports hundreds of organizations globally. Customers run anywhere from a few thousand to hundreds of millions of active certificates on the platform.
• Industry recognition: Named the Growth and Innovation leader in the Frost & Sullivan Frost Radar for PKI as a Service.
• Post-quantum ready: PQC-capable PKI with advanced certificate discovery and automation to identify and migrate to quantum-safe standards. Owning the cryptographic libraries gives Keyfactor a unique advantage in integrating post-quantum algorithms rapidly.
• Limitless scalability: Single-tenant cloud infrastructure with high-availability, geo-redundant options, and over 100 pre-built integrations.
• SLA-driven support: 24/7/365 service monitoring, SOC 2 Type II and ISO 27001 certified (audited annually), with high support satisfaction ratings.