Secure Device Functionality Enablement with Ephemeral HMAC Authentication
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Secure processing devices face vulnerabilities due to the storage of credentials or reusable cryptographic keys, which can lead to security breaches and unauthorized access.
Innovation Solution
A method involving the generation of a unique hashed-based message authentication code (HMAC) key, using device-unique data, and a trusted device's private key to enable secure device functionality without storing credentials or reusable keys, with temporary enablement conditions and key expiration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If credentials or reusable cryptographic keys are stored in the secure device, then unlocking and access control becomes simpler, but security vulnerability increases
Solution Approach 1:
The patent extracts the credential storage function from the secure device itself. Instead of storing credentials or reusable cryptographic keys in the device, it uses ephemeral cryptographic keys that are generated temporarily, used for authentication, and then discarded. This removes the vulnerable credential storage component while maintaining authentication capability.
Solution Approach 2:
The patent introduces dynamic cryptographic keys that change with each authentication session. Rather than static credentials, the system generates ephemeral keys that are valid only for a single authentication event, making each authentication instance unique and non-reusable, thereby preventing credential theft and replay attacks.
2Object-affected harmful factors
If ephemeral cryptographic keys are generated and discarded after use, then security is improved, but key management complexity increases
Solution Approach 1:
The patent introduces a key management server as an intermediary that handles the generation, distribution, and revocation of ephemeral cryptographic keys. This externalizes the complex key management tasks from the secure device, allowing the device to focus on its primary security functions while the server manages the lifecycle of ephemeral keys including their generation from device-unique data and their secure distribution to authorized devices.
3Object-affected harmful factors
If temporary enablement with expiration conditions is implemented, then security control is improved, but operational flexibility decreases
Solution Approach 1:
The patent implements dynamic enablement of device functionality based on authentication success and configurable expiration conditions. Functionality is temporarily enabled when ephemeral key authentication succeeds and can be configured to expire after a predetermined time period, number of power cycles, or number of times the functionality is enabled. This creates adaptable security control that can respond to different operational scenarios while maintaining security through automatic expiration.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method is provided for temporarily enabling functionality of a secure device. The method includes storing public keys for respective trusted devices of at least one trusted device, storing device-unique data that is unique for the secure device, generating a unique hashed-based message authentication code (HMAC) key, computing, based on the HMAC key and the device-unique data, a unique HMAC, transmitting the HMAC to a trusted device of the at least one trusted device, receiving a signed HMAC from the trusted device, wherein the signed HMAC is the HMAC as signed by the trusted device using a private key of the trusted device, decrypting the signed HMAC using the public key for the trusted device, comparing the decrypted signed HMAC to the HMAC, and enabling functionality of the secure device based on a result of the comparison.