Secret Share Regeneration Using Blinding Shares and Threshold Changes
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Solution Overview
Problem
Existing methods fail to efficiently generate new shares of a shared secret without altering the shared secret itself, replace compromised or lost shares, or adjust the threshold of participants required to reconstruct the shared secret, particularly in scenarios involving shared private keys.
Innovation Solution
A computer-implemented method involving a first participant generating a blinding share and obtaining intermediary shares from other participants to create new secret shares based on these and the blinding share, allowing for the generation of new shares that can increase or decrease the number of participants needed to reconstruct the shared secret.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If new shares of a shared secret are generated using existing methods, then the shared secret can be redistributed, but the shared secret itself is altered and old shares remain valid
Solution Approach 1:
The patent introduces a blinding share as an intermediary element that is combined with existing shares to generate new shares. The blinding share acts as a mediator that transforms the original shares into new shares without altering the underlying shared secret, thereby maintaining security while enabling share regeneration and participant management.
2Reliability
If the threshold of participants is adjusted to improve security, then more participants are needed to reconstruct the secret, but the complexity of share management increases
Solution Approach 1:
The patent enables dynamic adjustment of the threshold parameter in the secret sharing scheme. By changing the threshold value, the system can adapt security requirements without requiring complete redistribution of shares. The blinding share mechanism allows smooth transition between different threshold levels while maintaining share validity and simplifying management.
3Reliability
If old shares are replaced to render them useless against attackers, then security is improved, but the ability to maintain continuity of the shared secret is compromised
Solution Approach 1:
The blinding share serves as a mediator that enables the transformation from old shares to new shares while preserving the underlying shared secret. This intermediary mechanism ensures that old shares become invalid (improving security) while the shared secret remains accessible through new shares (maintaining continuity), thereby resolving the contradiction between security and stability.
Data Source
AI summary
A computer-implemented method of generating shares of a shared secret, wherein each of a group of participants has a respective first secret share of the shared secret, wherein the method is performed by a first participant of the group and comprises: generating a respective blinding share of a shared blinding secret, obtaining at least a threshold number of respective intermediary shares from each of the first group of participants, wherein each respective intermediary share is generated based on a respective blinding share and a respective first secret share; generating an intermediary value based on each of the obtained intermediary shares; and generating a respective second secret share of the shared secret, wherein the respective second secret shared is generated based on the intermediary value and the respective blinding share.