OPRF-Based Key Management Service for Secure Key Segmentation
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Solution Overview
Problem
Existing Key Management Systems (KMSs) lack adequate means to organize, process, and secure keys, especially when trust in service providers is compromised, leading to vulnerabilities in key management and access.
Innovation Solution
The implementation of an Oblivious Pseudorandom Function (OPRF)-based Key Management System that generates key identifiers and performs key wrap and unwrap semantics, using blinding operations to ensure key secrecy and security, eliminating the need for centralized servers and Hardware Security Modules (HSMs).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If traditional centralized KMS is used, then key management is simplified, but trust in service provider is required and security is compromised
Solution Approach 1:
The system segments key management into two independent parts: the client holds encryption keys locally without exposing them to the service provider, while the service provider maintains oblivious access to encrypted data. This segmentation eliminates the trust requirement while maintaining operational simplicity.
Solution Approach 2:
Homomorphic encryption acts as an intermediary mechanism that allows the service provider to perform operations on encrypted data without decrypting it. The blinded key identifiers serve as mediators that enable the service provider to access the correct encryption keys without the client exposing their key material.
2Ease of manufacture
If service provider has access to encryption keys, then key management is straightforward, but vulnerability to malicious insiders and attackers increases
Solution Approach 1:
The system extracts the encryption keys from the service provider's environment and keeps them exclusively on the client side. The service provider only receives blinded key identifiers that cannot be reverse-engineered to reveal the original keys, thereby eliminating the security vulnerability while maintaining implementation feasibility.
Solution Approach 2:
The client performs preliminary blinding of key identifiers before transmitting them to the service provider. This preliminary action ensures that the service provider never receives unblinded key material, preventing potential security breaches while allowing straightforward key management operations.
3Reliability
If OPRF blinding operations are implemented, then key secrecy is enhanced, but computational complexity increases
Solution Approach 1:
The system replaces complex mechanical security devices like HSMs with cryptographic blinding operations. The OPRF-based blinding mechanism achieves the same security goals as hardware-based solutions but with software implementation, reducing device complexity while maintaining key secrecy.
Data Source
AI summary
A computing device includes an interface configured to interface and communicate with a communication system, a memory that stores operational instructions, and processing circuitry operably coupled to the interface and to the memory that is configured to execute the operational instructions to perform various operations. The computing device generates a sub-key identifier based on a data ID, which is based on unique ID value(s) associated with an encrypted data object, and a requester secret. The computing device processes the sub-key identifier in accordance with an Oblivious Pseudorandom Function (OPRF) blinding operation to generate a blinded input and an Oblivious Key Access Request (OKAR). The computing device transmits the OKAR to another computing device (e.g., Key Management System (KMS) service) and receives a blinded sub-key therefrom. The computing device processes the blinded sub-key in accordance with an OPRF unblinding operation to generate the key and accesses secure data thereby.