Adjustable Quorum Blockchain Sharding for Scalability
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Solution Overview
Problem
Existing blockchain sharding protocols face challenges in ensuring security and scalability due to the risk of shard corruption by malicious nodes, which increases exponentially with network size, limiting the ability to create arbitrarily small shards and compromising the integrity of the protocol.
Innovation Solution
The solution involves adjusting the quorum size for consensus protocols within network shards to prevent malicious nodes from forming a quorum, while ensuring that honest nodes can always form a quorum in some shards, and implementing a cross-shard transaction verification protocol to reduce inter-shard communication and storage overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the network shard size is reduced to increase transaction throughput, then productivity is improved, but the reliability deteriorates due to increased likelihood of corrupt shards
Solution Approach 1:
The patent changes the quorum parameter from a fixed threshold to a dynamically adjusted value based on the fraction of corrupt nodes. By setting the quorum to f/(2f-1) where f is the fraction of corrupt nodes, the system adapts the consensus threshold to the actual security conditions, allowing smaller shards to operate securely when corruption is low while maintaining reliability even as shard size decreases
Solution Approach 2:
The system implements dynamic quorum adjustment where the quorum threshold is not static but varies according to the corruption fraction f. This dynamic parameter allows the shard to optimize its consensus requirements based on current security conditions, enabling flexible operation across different shard sizes and corruption levels
2Reliability
If the quorum size is increased to prevent corrupt shard formation, then reliability is improved, but the productivity deteriorates due to slower consensus
Solution Approach 1:
The patent optimizes the quorum parameter to the specific value of f/(2f-1) rather than using conservative fixed thresholds. This precise parameter setting achieves the minimum required quorum for security, eliminating unnecessary delays from overly conservative quorum sizes while maintaining reliable protection against corrupt nodes
Solution Approach 2:
The system applies the minimum necessary quorum threshold rather than excessive conservative thresholds. By using exactly f/(2f-1) which is the precise point where security is achieved, the system avoids the performance penalty of using higher quorum values that would provide marginal security improvements
3Productivity
If cross-shard communication is reduced to improve scalability, then productivity is improved, but the measurement precision deteriorates in verifying transactions
Solution Approach 1:
The patent extracts the verification function from the consensus process itself. By separating verification (which can be done independently by any node) from consensus (which requires quorum), the system allows transactions to be verified without requiring communication with other shards, improving scalability while maintaining verification accuracy
Solution Approach 2:
The system performs verification as a preliminary action before consensus is required. Nodes can verify transactions independently in advance, and only need to communicate with the quorum for final consensus, reducing the communication overhead during critical transaction processing while maintaining thorough verification
Data Source
AI summary
A method includes broadcasting, by a node computer, a propose message comprising a new block for a blockchain to a plurality of node computers in a network shard. The node computer can receive at least one vote message from the plurality of node computers, the at least one vote message indicating verification of the new block. The node computer can, after a predetermined amount of time, receive a plurality of pre-commit messages comprising at least the new block and a block certificate created based on the at least one vote message. If the number of received pre-commit messages of the plurality of pre-commit messages is greater than a quorum value associated with the network shard, the node computer can commit the new block to the blockchain.