ISO 15118 is a communications standard for secure electric vehicle charging and vehicle-to-grid interaction. It defines encrypted, authenticated communication between vehicles and charging infrastructure, supporting trust in plug-and-charge workflows and helping reduce risks such as session manipulation, spoofing, and grid-related abuse during charging operations.
What ISO 15118 Does in EV Charging
ISO 15118 sits at the trust boundary between the vehicle and the charging system. It enables secure message exchange for charging sessions and vehicle-to-grid interactions, so the charger can recognise the vehicle, the vehicle can validate the charger, and the workflow can proceed without relying on manual steps that are easier to spoof or manipulate.
That trust model matters because charging is not just a power transaction, it is also a control relationship. When communications are encrypted and authenticated, the system can reduce exposure to session hijacking, fraudulent plug-and-charge initiation, and interference with charging state or billing logic.
How ISO 15118 Supports Secure Plug-and-Charge Workflows
The best-known use of ISO 15118 is Plug and Charge, where the car presents credentials and the charging infrastructure can establish trust automatically. That removes friction for drivers, but it also raises the bar for certificate handling, backend trust, and interoperability across vehicle manufacturers, charge point operators, and roaming ecosystems.
In practice, ISO 15118 is only one part of a broader EV charging security stack. It often works alongside back-end protocols, operator policy, and PKI governance, so the security outcome depends on the whole trust chain, not just the wire protocol between vehicle and charger. NHIMG’s EV Charging Security Guide covers that wider operating model, including Plug and Charge PKI and charge point security considerations.
Why Trust and Authentication Matter in Vehicle-to-Grid Communications
Vehicle-to-grid interaction extends ISO 15118 beyond a single charging event. The protocol can influence when energy is drawn, how much is delivered, and how that exchange is authorised, which means the communications channel becomes part of operational and sometimes grid-edge control.
That is why authenticated messaging is central. If a charging session can be impersonated, replayed, or altered, an attacker may be able to create bogus charging states, disrupt billing, or trigger unsafe or unauthorised energy flows. The protocol is designed to make those actions harder by binding the session to trusted credentials and protected exchanges.
NHIMG’s Automotive Cybersecurity Guide is useful context here because ISO 15118 sits alongside vehicle cybersecurity controls, PKI trust, and broader V2X security patterns.
Where ISO 15118 Exposure Typically Appears
Exposure usually comes from weak implementation rather than the standard itself. The common failure points are certificate lifecycle mistakes, inconsistent support across vehicle and charger vendors, poor validation of peers, and insecure backend integrations that undermine the trust established on the charging link.
Because charging ecosystems combine hardware, software, operator back ends, and roaming trust, organisations should treat ISO 15118 as an end-to-end security dependency. A secure protocol exchange can still be undermined if device inventory is incomplete, if insecure defaults remain enabled, or if operational controls do not detect abnormal charging behaviour.
Risk and Threat Considerations
ISO 15118 reduces several charging-specific risks, but it also concentrates trust into a highly valuable authentication and session-control path. If that path is misconfigured or poorly implemented, attackers can target credentials, certificates, or session logic to impersonate vehicles, spoof chargers, or interfere with charging transactions and downstream grid interactions.
Failure mechanism: Weak certificate handling, replayable session logic, or inadequate peer validation can let an attacker inject themselves into the trust relationship and manipulate charging state or authorisation decisions.
Impact: The result can include fraudulent charging, session tampering, service disruption, billing abuse, and, in some environments, unsafe or unauthorised grid-edge behaviour.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST SP 800-53 Rev 5, NIST SP 800-57, CIS Controls v8 and NIST CSF 2.0 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST SP 800-53 Rev 5 | IA-9 — Service Identification and Authentication | ISO 15118 depends on authenticated machine-to-machine trust between vehicle and charger. |
| IA-5 — Authenticator Management | Plug and Charge relies on certificates and credential lifecycle discipline. | |
| Recommendation — Apply IA-9 to authenticate charging peers and protect the session trust boundary. Manage charging certificates through rotation, revocation, and secure storage. | ||
| NIST SP 800-57 | Key Management | ISO 15118 security depends on certificate and key lifecycle governance. |
| Recommendation — Define key lifecycle rules for charging PKI, including generation, rotation, and destruction. | ||
| CIS Controls v8 | CIS-5 — Account Management | Charging ecosystems need controlled lifecycle and ownership for trusted access paths. |
| Recommendation — Inventory and govern all charging-related trust accounts and access paths. | ||
| NIST CSF 2.0 | PR.AA-05 — Authentication for Assets and Services | ISO 15118 is about authenticated trust between assets and services in the charging path. |
| Recommendation — Use authenticated communications for charger, vehicle, and backend interactions. | ||
Practitioner Guidance
What to watch for: Treat ISO 15118 as a cryptographic trust system, not just a vehicle interface. The operational question is whether every charger, vehicle, and backend component participating in the workflow can reliably validate peers, manage certificates, and detect abnormal session behaviour over time.
Governance implication: Ownership should span vehicle-side implementation, charging infrastructure, PKI operations, and backend monitoring. If those responsibilities are split across vendors or business units, the trust model can fail at the seams even when the protocol itself is correctly specified.
Practitioner takeaway: Secure Plug and Charge depends on the integrity of the full certificate and session lifecycle, so the charging protocol, the trust infrastructure, and the monitoring controls must be designed and operated as one system.
Related resources from NHI Mgmt Group
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Reviewed and updated by the NHIMG editorial team on October 31, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org