Blinded Activation Codes for Digital Certificate Revocation
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Solution Overview
Problem
The large-scale deployment of V2X technologies faces challenges in ensuring message legitimacy and user privacy, particularly with the growth of certificate revocation lists (CRLs) due to misbehaving vehicles, which increases computation costs and network bandwidth, and poses security risks from colluding certificate management entities.
Innovation Solution
The implementation of certificate management techniques using activation codes, where pseudonym certificates are generated in batches and activated with 'just-in-time' activation codes, reducing CRL size and enhancing security by preventing collusions between Certificate Access Manager and Pseudonym Certificate Authority.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If certificate revocation lists (CRLs) are distributed to ensure message legitimacy, then security is improved, but CRL size increases computation costs and network bandwidth consumption
Solution Approach 1:
The patent extracts the essential revocation information from large CRLs by using activation codes that can be verified without processing the entire certificate revocation list. This allows vehicles to check revocation status efficiently by comparing their activation code against a compact revocation set, significantly reducing computation costs while maintaining security.
Solution Approach 2:
The patent segments the CRL verification process into two parts: a compact revocation set distributed to vehicles and full CRLs maintained by authorities. This segmentation allows lightweight verification at the vehicle level while centralizing the heavy lifting of CRL management, reducing both computation and network bandwidth requirements.
2Reliability
If certificate revocation lists (CRLs) are distributed to ensure message legitimacy, then security is improved, but CRL size increases network bandwidth consumption
Solution Approach 1:
The patent extracts only the essential revocation information needed for verification into compact activation code sets, eliminating the need to transmit and process large CRLs across the network. This extraction approach dramatically reduces network bandwidth consumption while preserving the ability to verify message legitimacy.
Solution Approach 2:
The patent segments network communication into selective activation code updates rather than continuous CRL distribution. This segmentation reduces network traffic by only transmitting revocation information when changes occur, minimizing bandwidth consumption while maintaining security.
3Adaptability or versatility
If pseudonym certificates are used to protect user privacy, then anonymity is improved, but the ability to revoke certificates is complicated
Solution Approach 1:
The patent introduces activation codes as an intermediary mechanism that links pseudonym certificates to their revocation status without exposing the connection between multiple pseudonyms and the same user. This intermediary allows authorities to revoke certificates by invalidating activation codes, simplifying the revocation process while preserving user anonymity.
Solution Approach 2:
The patent segments the certificate system into pseudonym certificates for privacy protection and activation codes for revocation control. This segmentation allows independent optimization of each component: pseudonyms protect anonymity while activation codes enable simple revocation, reducing overall system complexity.
Data Source
AI summary
To revoke a digital certificate (160p), activation of the digital certificate is blocked by withholding an activation code from the certificate user (110). The certificates are generated by a plurality of entities (210, 220, 838) in a robust process that preserves user privacy (e.g. anonymity) even in case of collusion of some of the entities. The process is suitable for connected vehicles, e.g. as an improvement for Security Credential Management System (SCMS).