EVCC Contract Certificate Key Installation Without TPM
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Solution Overview
Problem
Existing communication technologies for electric vehicles face security threats due to the difficulty in verifying a trusted certification authority in real time and vulnerability to unauthorized access, particularly when using TLS and electronic signatures without a trusted platform module (TPM), necessitating a secure method for transmitting and decrypting contract certificate private keys.
Innovation Solution
A method and apparatus using AES-Galois/counter mode (GCM) encryption based on ECDH protocol to securely transmit and decrypt contract certificate private keys to an electric vehicle communication controller (EVCC) without a trusted platform module, ensuring high confidentiality and integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TLS and electronic signatures are used without a trusted platform module (TPM), then communication can be established between EV components, but security is vulnerable to unauthorized access and difficulty in verifying trusted certification authority
Solution Approach 1:
The patent applies preliminary action by pre-installing a root certificate in the EVCC before actual communication occurs. This root certificate serves as a trusted anchor that enables subsequent verification of contract certificates and authentication of communication partners, eliminating the need for TPM while establishing security trust in advance
Solution Approach 2:
The patent uses an intermediary approach by introducing a certificate provisioning service (CPS) that acts as a trusted mediator between the EVCC and external entities. The CPS issues contract certificates and manages the certificate lifecycle, enabling secure communication without requiring TPM hardware by delegating trust management to a software-based intermediary service
2Reliability
If contract certificate private key is transmitted without encryption, then installation process is simple, but confidentiality and integrity are compromised against unauthorized access
Solution Approach 1:
The patent applies parameter changes by transforming the private key from plaintext to encrypted form using AES-GCM encryption. The encryption parameters include a randomly generated initialization vector (IV) and a decryption key, which are transmitted alongside the encrypted key. This parameter transformation enables secure transmission while maintaining the ability to decrypt and install the key on the EVCC
Solution Approach 2:
The patent uses preliminary action by pre-generating the decryption key and IV before encrypting the private key. These decryption parameters are prepared in advance and transmitted to the EVCC along with the encrypted key, enabling the EVCC to autonomously decrypt and install the private key without requiring external decryption assistance, thus maintaining ease of operation while ensuring confidentiality
Data Source
AI summary
Disclosed are a method and device for installing a certificate on the basis of encryption and decryption of a contract certificate private key for an electric vehicle communication controller. The method for installing the certificate comprises: a step in which the electric vehicle communication controller transmits, to a secondary actor, a certificate installation request message signed with a private key associated with a manufacturer's provisioning certificate; and a step of receiving, from the secondary actor, a certificate installation response message signed with a private key associated with a leaf certificate of a certificate provisioning service, wherein an encrypted private key element of the certificate installation response message stores a private key belonging to a new contract certificate which is encrypted for the electric vehicle communication controller without a trust platform module, the private key belonging to the new contract certificate is encrypted with AES-GCM-256 on the basis of an encryption key which is entered from a public key of the manufacturer's provisioning certificate and generated through an ECDH protocol, and the private key encrypted with the AES-GCM-256 is included in a ciphertext at 528-bits or 448-bits after an initial initialization vector of a contract certificate data packet.