Tamper-Evident Data Store Pruning with Hash-Linked DAGs
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Solution Overview
Problem
Existing tamper-evident data structures pose challenges in efficiently pruning entries while maintaining the ability to detect tampering, particularly in decentralized computing platforms like blockchains, due to computational infeasibility and immutability constraints.
Innovation Solution
Implement a process for pruning entries in tamper-evident data stores using a directed acyclic graph of cryptographic hash pointers, allowing selective removal of program states while preserving cryptographic proof of membership and tamper-evident properties, utilizing a virtual machine with pruning opcodes and consensus algorithms to ensure data integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If entries are pruned from the tamper-evident data store, then storage efficiency and data management are improved, but the ability to maintain cryptographic consistency and detect tampering deteriorates
Solution Approach 1:
The data store is segmented into different subsets of cryptographic hash pointers (first subset, second subset, third subset) that can be independently managed. This allows selective pruning of specific program states while preserving the cryptographic integrity of remaining data through maintained linkages between subsets.
Solution Approach 2:
A record is introduced as an intermediary element that links the first subset of cryptographic hash pointers to the second subset. This intermediary maintains the cryptographic proof of membership and tamper-evident properties even after pruning operations, bridging the gap between pruned and retained data.
2Reliability
If one-way functions are used to ensure tamper evidence, then security and tamper detection are improved, but computational complexity and processing time worsen
Solution Approach 1:
Cryptographic hash values are pre-computed and stored in the data structure before any pruning operations occur. The directed acyclic graph of cryptographic hash pointers is constructed in advance with all necessary hash values, allowing efficient pruning without requiring re-computation of one-way functions during the pruning process.
3Reliability
If all program states are retained in the data store, then complete auditability and tamper detection are improved, but storage requirements and system complexity worsen
Solution Approach 1:
The system enables discarding of pruned program states from the tamper-evident data store while recovering and preserving the cryptographic proof of their former existence through the directed acyclic graph structure and linking records. This allows storage optimization while maintaining auditability of historical states.
4Adaptability or versatility
If pruning operations are implemented, then data management flexibility and storage efficiency are improved, but the risk of introducing inconsistencies and compromising data integrity worsens
Solution Approach 1:
The directed acyclic graph of cryptographic hash pointers provides continuous feedback on the integrity of the data store. Each hash pointer validates the state of its target, and the linking record between subsets ensures that pruning operations maintain cryptographic consistency. Any attempt to introduce inconsistencies would be detected through this feedback mechanism.
Data Source
AI summary
Provided is a process that includes pruning entries in a tamper-evident data store while maintaining tamper-evident properties of prior and subsequent entries after pruning. Operations include traversing a linked list of instances of program state of a smart contract in the tamper-evident data store and pruning identified instances of program state in the tamper-evident data store.