A TPM (Trusted Platform Module) is a dedicated hardware security component that provides a root of trust for a device. It securely stores cryptographic keys and performs security functions such as key generation, signing, encryption, and device integrity checks. In EV charging, TPMs (or TPM-like secure elements) are used to strengthen charger cybersecurity by protecting identities, certificates, and firmware trust mechanisms.
A TPM helps ensure the charger is the device it claims to be and that critical secrets cannot be easily extracted, even if someone gains physical access.
Why TPMs Matter in EV Charging
EV chargers are deployed in public and semi-public environments and are connected to networks, payment systems, and control platforms. A TPM supports:
– Strong device identity for secure charger-to-backend communication (TLS, mTLS)
– Secure storage of private keys used in PKI and certificate-based authentication
– Protection against cloning or credential theft from compromised devices
– Measured boot / integrity verification to detect firmware tampering
– Stronger security for OCPP security profiles and secure provisioning workflows
– Reduced risk that a physical breach leads to network compromise
For public networks, TPM-backed identity and secure boot can significantly reduce cybersecurity risk.
What a TPM Typically Does
TPM functions commonly used in connected devices include:
– Secure key generation and storage (private keys never leave the TPM unencrypted)
– Cryptographic operations (signing, encryption, decryption)
– Device attestation (proving the device state to a remote server)
– Secure boot support (measuring firmware and bootloader integrity)
– Protected storage of secrets like certificates, tokens, and credentials
– Anti-rollback support (preventing downgrade to vulnerable firmware, depending on implementation)
How TPMs Are Used in EV Chargers
In EV charging systems, TPMs are often used to:
– Store TLS client certificates for charger authentication (mTLS)
– Protect provisioning credentials and onboarding keys during manufacturing and deployment
– Support secure firmware updates (signature verification and trust anchoring)
– Enable tamper-aware security designs when combined with tamper detection
– Provide audit-friendly device identity controls for fleets and regulated deployments
TPMs are often part of a broader hardware security module (HSM) approach for embedded devices.
TPM vs Secure Element vs HSM
Terms vary by implementation:
– TPM is a standardized security module interface used widely in computing
– A secure element is a similar concept used in embedded devices and IoT (often smaller, purpose-built)
– An HSM usually refers to a higher-end module used in servers or data centers
In EV chargers, you may see TPMs or secure elements used for device identity and secure storage, while backend systems may use HSMs for certificate authority and key management.
Operational Considerations
– Certificate lifecycle management still matters (expiry, renewal, rotation) even with TPMs
– TPM integration must be designed into manufacturing and provisioning workflows
– Secure boot and signed firmware require disciplined update pipelines and key governance
– Physical access threats still exist; TPM reduces risk of key extraction but does not eliminate all risks
– Remote attestation adds complexity and must be supported by backend systems
Common Pitfalls
– Using a TPM but storing credentials outside it, weakening the security model
– Weak provisioning processes (shared keys, poor device identity tracking)
– Not monitoring certificate expiry, causing charger disconnects and downtime
– Treating TPM as “security solved” without firmware signing, patch management, and incident response
Related Glossary Terms
TLS Encryption
Mutual TLS (mTLS)
Public Key Infrastructure (PKI)
Digital Certificates
OCPP Security Profiles
Firmware Signing
Tamper Detection
EV Charging Cybersecurity