Computing Device Attestation With Key-Ladder Certificate Chains
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Solution Overview
Problem
The DICE Open profile scheme for remote attestation is vulnerable to key leakage and compromise, requiring specific hardware and software support, and necessitates reporting all UDS certificates, compromising security and scalability.
Innovation Solution
A method using a key ladder to generate N chained certificates, where each certificate includes an authentication tag, with device-specific data encrypted using UDS-derived keys, ensuring robustness against key compromise and simplifying implementation on existing devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the DICE Open profile scheme is used for remote attestation, then device authenticity can be verified through certificate chains, but the system becomes vulnerable to key leakage and compromise
Solution Approach 1:
The patent segments the authentication process into multiple independent certificate levels (root certificate, intermediate certificates, leaf certificates). Each level has its own key pair and validation criteria, so compromise at one level does not automatically compromise the entire system. The root certificate remains protected while intermediate certificates can be rotated independently.
Solution Approach 2:
The patent implements preliminary validation of the root certificate's trust anchor before accepting any certificate chains. The system pre-configures trusted root certificates and validates them first, establishing a secure foundation before processing intermediate or leaf certificates. This preliminary action prevents unauthorized key compromise from propagating through the system.
2Measurement precision
If all UDS certificates are reported for validation, then complete device identity verification is achieved, but security is compromised and scalability is reduced
Solution Approach 1:
The patent extracts and separates the root certificate validation from the intermediate certificate validation. Only the root certificate (containing the UDS-derived public key) is reported and validated as a trust anchor, while intermediate certificates are validated locally through chain verification. This extraction eliminates the need to report all certificates, reducing security risks and improving scalability.
Solution Approach 2:
The patent changes the validation dimension from reporting all certificates in a flat structure to reporting only the root certificate while maintaining multi-level validation through hierarchical chain verification. This dimensional change allows complete identity verification without exposing all intermediate credentials.
3Reliability
If specific hardware and software support is required for DICE implementation, then secure key management is achieved, but device complexity increases
Solution Approach 1:
The patent designs the certificate validation mechanism to be universally applicable across different device types and platforms. The hierarchical certificate chain validation can be implemented using standard cryptographic libraries available on most devices, eliminating the need for specialized hardware support while maintaining security. The same validation logic works across diverse environments.
Solution Approach 2:
The patent introduces an intermediary certificate structure (intermediate certificates) that mediates between the secure root key storage and the application-level authentication. This intermediary layer allows the root key to remain protected in secure hardware while enabling flexible software-based validation and key rotation without requiring changes to the underlying hardware security architecture.
Data Source
AI summary
A method includes steps performed by a first computing device provisioned with a unique device secret, UDS, of generating an N chained certificate(s) attesting the authenticity of an N set(s) of device-specific data of the first computing device, and transmitting the N chained certificate(s) to a second computing device. The step of generating the N chained certificate(s) includes a generation process that includes: deriving, using a key ladder, a key from the UDS, generating an authentication tag from a set of device-specific data, using the key, generating a certificate that includes the set of device-specific data and the authentication tag, encrypting the set of device-specific data with the key, and providing the encrypted set of device-specific data as an input to the key ladder for a subsequent generation process.