A Trusted Platform Module (TPM) is a dedicated hardware security component that provides a device with a hardware root of trust. It securely generates, stores, and uses cryptographic keys, helping protect a charger’s identity, communications, and firmware integrity. In EV charging, a TPM (or TPM-like secure element) strengthens cybersecurity by making it much harder to extract private keys or clone devices.
Why TPMs Matter in EV Charging
EV chargers are network-connected devices deployed in public or semi-public environments, so they face both cyber and physical threats. A TPM helps:
– Secure device identity for charger-to-backend authentication (TLS, mTLS)
– Protect private keys and certificates used in PKI
– Reduce risk of credential theft during physical tampering attempts
– Support secure boot and firmware integrity checks (detect modified firmware)
– Improve compliance posture for EV charging cybersecurity expectations
– Reduce the chance that one compromised charger becomes a gateway into the network
What TPMs Typically Do
A TPM commonly provides:
– Secure key generation and protected key storage
– Cryptographic operations (signing, encryption/decryption) inside the TPM
– Device attestation (proving the device’s software state to a remote system)
– Measured boot support (hashing boot components to detect changes)
– Optional anti-rollback mechanisms to prevent downgrades to vulnerable firmware (implementation-dependent)
How TPMs Are Used in Charging Systems
In EV charging deployments, TPM-backed security is often applied to:
– OCPP over TLS with certificate-based charger authentication
– Secure provisioning workflows (device onboarding, certificate enrollment)
– Firmware update validation (signed firmware images, integrity checks)
– Protecting long-lived credentials (client certificates, private keys, tokens)
– Supporting incident response workflows (revoking device certificates if compromised)
TPM vs Secure Element vs Backend HSM
– A TPM is a standardized type of hardware security module on the device
– A secure element provides similar capabilities in embedded/IoT form factors
– A backend HSM is typically used server-side (e.g., to protect CA keys for PKI)
Many EV charging ecosystems use a secure element/TPM in the charger and an HSM in the backend.
Operational Considerations
– Certificate lifecycle management is still required (expiry, renewal, rotation)
– Chargers need correct timekeeping for certificate validation
– Provisioning processes must uniquely bind certificates to each charger
– TPM improves key protection but does not replace patching, monitoring, and access control
– Integration should be designed to avoid downtime from misconfigured certificates
Common Pitfalls
– Storing keys outside the TPM, undermining the root-of-trust benefit
– Weak provisioning practices (shared keys, poor asset identity records)
– No monitoring for certificate expiry leading to charger disconnects
– Assuming TPM alone solves cybersecurity without secure firmware and incident response
Related Glossary Terms
TLS Encryption
Mutual TLS (mTLS)
Public Key Infrastructure (PKI)
OCPP Security Profiles
Firmware Signing
EV Charging Cybersecurity
Tamper Detection
Incident Response