Key Delivery System Using Secret Sharing and Device Verification
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Solution Overview
Problem
The existing key management systems are not designed for distributed management, leading to risks of secret information leakage due to inadequate security measures at individual sites, and there is a lack of effective methods for verifying the validity of devices involved in secret sharing.
Innovation Solution
A key delivery system that employs a secret sharing scheme with a (k, n) threshold configuration, where share data is encrypted and distributed across multiple devices, and a verification method is used to authenticate the capabilities of each device without relying on key exchange, ensuring that invalid share data is detected through a distributed and series decryption process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If secret sharing scheme is used to distribute encryption key across multiple devices, then security against single-point failure is improved, but device complexity increases due to need for coordination and verification mechanisms
Solution Approach 1:
The encryption key is segmented into multiple share data pieces distributed across different devices. Each device holds only a portion (share data) of the original key, and the key can be reconstructed only when a sufficient number of shares are combined. This segmentation prevents single-point failure and enhances security while managing complexity through modular distribution.
2Reliability
If distributed management is implemented across multiple sites, then business continuity is improved, but risk of information leakage increases due to inadequate security measures at individual sites
Solution Approach 1:
The encryption key is divided into multiple share data segments distributed across different geographic sites. Each site receives only a portion of the key material, making it impossible for any single compromised site to obtain the complete key. This ensures business continuity across distributed locations while mitigating information leakage risk through spatial segmentation.
Solution Approach 2:
Different sites receive different types or levels of share data based on their specific security capabilities and trust levels. The system allows for heterogeneous security measures at different locations, with each site having appropriately tailored security requirements rather than imposing uniform high-security standards everywhere.
3Reliability
If (k, n) threshold scheme is used for key restoration, then redundancy is improved allowing key recovery from k out of n shares, but device complexity increases due to verification and coordination requirements
Solution Approach 1:
Verification of device validity and share data authenticity is performed preliminarily before the key restoration process begins. The transmission source verification part and transmission destination verification part conduct checks in advance to ensure that only valid shares from authorized devices are used for reconstruction, preventing wasted computational effort on invalid combinations and simplifying the overall process.
4Ease of operation
If share data is transmitted between devices, then distributed decryption is enabled, but risk of wiretapping on communication path increases
Solution Approach 1:
The system moves the verification process to a different dimension by implementing mutual verification between transmission source and destination devices. Rather than relying solely on secure communication channels, the verification occurs at the protocol level between endpoints, adding a new layer of security that operates independently of the communication path's physical security.
Data Source
AI summary
A key delivery system, includes: a key issuance apparatus generating and issuing an encryption key; a distribution apparatus including: a share data generation part electronically dividing the encryption key into share data using a secret sharing scheme, a transmission destination verification part verifying validity of a transmission destination in transmitting the share data, and a share data transmission part transmitting the share data to the transmission destination, when a verification result obtained by the transmission destination verification part is valid; and a decryption apparatus including: a transmission source verification part verifying validity of a transmission source, in receiving the share data, a share data reception part receiving the share data from the transmission source when a verification result obtained by the transmission source verification part is valid, and a decryption part decrypting the encryption key using the share data received, as an input value.