PKI infrastructure (Public Key Infrastructure) is the set of technologies, policies, and processes used to create, manage, distribute, validate, and revoke digital certificates and cryptographic keys. PKI enables trusted identity verification and encrypted communications between systems—such as EV chargers, vehicles, backend platforms, and payment or roaming services.
Why PKI Infrastructure Matters in EV Charging
EV charging is a connected ecosystem with many parties (CPOs, eMSPs, OEMs, fleet operators). PKI is critical for:
– Secure TLS connections between chargers and backend systems
– Strong device identity (proving a charger or server is legitimate)
– Enabling Plug & Charge under ISO 15118
– Reducing risk of man-in-the-middle attacks, impersonation, and data tampering
– Meeting enterprise cybersecurity requirements and supporting standards-based security architectures
Core Components of PKI Infrastructure
A typical PKI setup includes:
– Certificate Authority (CA): issues and signs certificates (root CA and intermediate CAs)
– Registration Authority (RA): validates identities before certificates are issued (optional role)
– Certificates: bind a public key to an identity (device, server, organization)
– Private keys: securely stored keys used to authenticate and decrypt/sign
– Certificate lifecycle systems: enrollment, renewal, rotation, and decommissioning
– Revocation services: CRL (Certificate Revocation List) and/or OCSP (Online Certificate Status Protocol)
– Policies and governance: certificate profiles, validity periods, trust chains, audit rules
– Secure key storage: HSM (Hardware Security Module) or secure elements/TPMs for protecting private keys
How PKI Infrastructure Works
PKI establishes trust using a certificate chain:
– A trusted root CA signs one or more intermediate CAs
– Intermediate CAs issue certificates to chargers, servers, and services
– Devices authenticate using certificates during mutual TLS (mTLS) or server TLS
– Systems validate the certificate chain, expiry dates, and revocation status
– Encrypted communication and authenticated sessions are established once trust is confirmed
PKI in EV Charging Use Cases
PKI is used across multiple layers of the charging ecosystem:
– OCPP security: TLS certificates for secure charger-to-CPMS communication (often mTLS)
– ISO 15118 Plug & Charge: vehicle and charger certificates enable automated authentication and contract-based charging
– Backend APIs and microservices: service-to-service authentication in cloud environments
– Device provisioning: secure onboarding of chargers during manufacturing and commissioning
– Firmware update security: certificate-based trust for secure update pipelines and signed updates (implementation-dependent)
Certificate Lifecycle Management Considerations
A robust PKI infrastructure includes operational processes for:
– Enrollment: initial certificate issuance during factory provisioning or site commissioning
– Renewal: replacing certificates before expiry without service interruption
– Rotation: regular key changes to limit risk if a key is exposed
– Revocation: quickly invalidating compromised or decommissioned certificates
– Inventory and monitoring: tracking certificate status, expiry alerts, and chain consistency
– Incident response: emergency revocation and re-issuance procedures after a security event
Key Benefits
– Strong authentication and trusted identity across distributed charging assets
– Encrypted communications that protect data confidentiality and integrity
– Standards-based enablement for ISO 15118 and secure OCPP deployments
– Reduced operational risk from impersonation and interception attacks
– Scalable trust model for large fleets of chargers and multi-operator ecosystems
Limitations and Practical Considerations
– Operational complexity: certificate issuance, renewal, and revocation must be automated at scale
– Key protection is critical; poor private-key handling undermines the entire PKI
– Revocation checking (CRL/OCSP) requires availability planning and correct device behavior offline
– Certificate expiries can cause large-scale outages if not monitored and renewed in time
– Multi-party ecosystems require careful trust-chain alignment and governance (who is the CA, who is trusted)
Related Glossary Terms
Public Key Infrastructure (PKI)
Digital Certificates
TLS / mTLS
Certificate Authority (CA)
CRL / OCSP
Hardware Security Module (HSM)
ISO 15118
Plug & Charge
OCPP 1.6 / 2.0.1
Encrypted Communications
Secure Update Pipeline