A secure element (SE) is a tamper-resistant hardware component that securely stores and uses sensitive data, such as cryptographic keys, certificates, and credentials. It provides a protected execution environment for cryptographic operations (e.g., signing, encryption, key agreement) so that private keys are not exposed to the main processor or application memory.
In EV charging, secure elements are commonly used to protect identities and keys for TLS, OCPP security, and ISO 15118 Plug & Charge credential handling.
Why Secure Elements Matter in EV Charging Infrastructure
EV chargers are connected, remotely managed devices that must authenticate to backends and sometimes to vehicles.
– Protects private keys used for charger identity and backend authentication
– Reduces risk of credential theft from malware or physical access attacks
– Enables stronger security for secure boot, firmware signing, and secure OTA updates
– Supports certificate-based ecosystems like PKI and Plug & Charge
– Helps meet cybersecurity expectations for public infrastructure deployments
A secure element is one of the most effective ways to harden a charger against both remote compromise and on-site tampering.
How a Secure Element Works
A secure element combines secure storage, cryptographic hardware, and anti-tamper protections.
– Private keys and secrets are generated or imported into the SE and stored internally
– Cryptographic operations happen inside the SE (signing, decrypting, key exchange)
– The main controller sends a request (e.g., “sign this challenge”), not the key itself
– Access rules control which operations are allowed and by which software module
– Many secure elements support secure key provisioning during manufacturing
– Some support secure counters and monotonic versioning for rollback protection
This architecture prevents extraction of secrets even if the host MCU is compromised.
Common Uses of Secure Elements in EV Chargers
– TLS client authentication to charging management systems (CSMS)
– OCPP security profiles (certificate storage, signing, mutual TLS)
– ISO 15118 credential storage for Plug & Charge (contract certificates, key material)
– Protecting device identity for provisioning and fleet management
– Supporting secure boot by storing public keys or verifying boot signatures
– Protecting payment and metering-related credentials in certain architectures
Secure Element vs TPM vs HSM
These are related security hardware concepts with different typical roles.
– Secure element (SE): embedded, device-level protection for keys and crypto operations
– TPM (Trusted Platform Module): standardized module often used in PCs/industrial gateways for attestation and measured boot
– HSM (Hardware Security Module): higher-end infrastructure device for server-side key management and signing (e.g., issuing certificates)
In charger fleets, SEs are common inside the charger, while HSMs are common in backend PKI or certificate services.
Key Benefits of Secure Elements
– Strong protection of private keys against software and many physical attacks
– Improves trust for certificate-based authentication and secure communications
– Enables scalable, secure provisioning across large charger fleets
– Reduces the blast radius of firmware vulnerabilities (keys remain protected)
– Supports long-term lifecycle security (key rotation, certificate renewal)
Limitations to Consider
– Requires careful integration (key provisioning, APIs, lifecycle processes)
– If provisioning is poorly designed, the supply chain becomes the weak point
– Costs more than purely software-based key storage
– Some designs can become vendor-locked depending on toolchains and libraries
– Physical tamper resistance is strong but not absolute—system security still matters
Related Glossary Terms
Secure boot
Firmware signing
PKI infrastructure
Public key infrastructure (PKI)
OCPP security profiles
TLS certificates
ISO 15118
Plug & Charge adoption
Secure OTA updates
Hardware root of trust