Hierarchical Private Key Share Generation
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Solution Overview
Problem
Existing cryptographic systems face challenges in preventing key reuse and enabling key recovery for shared private keys, particularly in threshold signature schemes where the private key is distributed among participants, making it difficult to regenerate or replace without compromising security.
Innovation Solution
A method for generating shares of private keys, where each participant contributes to a shared master private key, allowing for the derivation of additional private key shares and enabling key recovery through a hierarchical deterministic key structure, ensuring that no single participant has access to the entire private key.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shared private key is distributed among participants in a threshold signature scheme, then security is improved by preventing single-point compromise, but key recovery and key replacement become difficult
Solution Approach 1:
The private key is segmented into multiple shares distributed among participants. Each participant holds a share, and the key can be recovered by combining a threshold number of shares. This segmentation enables both security (no single participant has full access) and key recovery (shares can be recombined if lost or compromised).
Solution Approach 2:
The system performs preliminary key setup where a master private key is generated and segmented into shares before actual use. This preliminary action establishes the foundation for both secure operation and future key recovery, as the share structure is pre-configured to enable reconstruction without requiring access to the original master key.
2Productivity
If a shared private key is used for multiple signing operations, then operational efficiency is improved, but security is compromised due to key reuse
Solution Approach 1:
The system dynamically generates multiple child private keys from a single master private key share. Each child key can be used for different signing operations or purposes, eliminating key reuse while maintaining operational efficiency. The master key share remains static, but it can derive numerous unique child keys as needed.
Solution Approach 2:
The master private key share serves multiple functions: it can directly sign messages, derive child private keys for different purposes, and enable key recovery. This multi-functionality allows the system to maintain security while supporting diverse operational needs without reusing the same key for incompatible purposes.
3Adaptability or versatility
If hierarchical deterministic key structure is implemented, then key management flexibility is improved, but system complexity increases
Solution Approach 1:
The system implements a nested key hierarchy where child private keys are derived from the master private key share, which itself is derived from master key shares. This nesting provides structured key management with clear parent-child relationships, enabling flexible key derivation while organizing complexity in a manageable hierarchical structure.
Data Source
AI summary
A computer-implemented method of generating shares of private keys, wherein the method is performed by a first participant of a group of participants and comprises: obtaining a first seed share, wherein each other participant has a respective seed share; generating a first master private key share of a shared master private key, wherein the first master private key share is generated based on the first seed share and the respective seed share of each other participant, and wherein each other participant has a respective master private key share; and generating one or more first private key shares based on the first master private key share, wherein each first private key share is a share of a respective shared private key.