Sensor-Based Shared Key Agreement Over Untrusted Channels
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Solution Overview
Problem
Existing methods for generating shared secret cryptographic keys between computing devices over untrusted communication channels are complex and prone to difficulties, especially in ad-hoc scenarios, and often require additional out-of-band channels that can be susceptible to attackers.
Innovation Solution
A method involving error correction data and message authentication codes generated from sensor data, allowing devices to create shared cryptographic keys using untrusted communication channels by transmitting error correction data and message authentication codes between devices to reconcile and regenerate matching keys.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If public key infrastructure and out-of-band channels are used for key exchange, then security is improved, but device complexity and vulnerability to attackers increase
Solution Approach 1:
The patent extracts the essential elements needed for secure key generation (sensor data capturing environmental characteristics) and removes the complex public key infrastructure and out-of-band communication requirements. By using locally captured sensor data from the physical environment, the system achieves security without relying on complex external authentication mechanisms.
Solution Approach 2:
Each device independently captures sensor data from the shared physical environment and autonomously generates cryptographic keys using its own processing capabilities. The error correction code enables self-synchronization between devices without requiring external coordination or complex key exchange protocols, making the system self-sufficient.
2Reliability
If public key infrastructure is used for key exchange, then security is improved, but communication efficiency deteriorates
Solution Approach 1:
The patent performs preliminary action by capturing sensor data from the physical environment before the actual communication takes place. This pre-captured environmental data is then used to rapidly generate cryptographic keys, eliminating the need for time-consuming public key exchange protocols during the actual communication establishment.
3Reliability
If out-of-band channels are used for key exchange, then security is improved, but reliance on vulnerable communication channels increases
Solution Approach 1:
The patent converts the naturally occurring variations in environmental sensor data (which could be seen as noise or uncertainty) into a beneficial feature. These variations, caused by different device positions and orientations in the physical environment, create unique cryptographic key material that is inherently difficult for attackers to replicate, turning environmental uncertainty into security strength.
Data Source
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AI summary
A method of generating cryptographic keys includes generating, with a first processor in a first computing device, error correction data corresponding to first sensor data that are stored in a memory, generating a first cryptographic key with reference to a first hashed value of the first sensor data, generating a first message authentication code (MAC) with reference to the first cryptographic key and the error correction data, and transmitting with a first I/O device in the first computing device the error correction data and the first MAC through a communication channel to a second computing device. The transmitted data enable the second computing device to generate a second cryptographic key with reference to second sensor data.