Garbled Circuit Server Consistency Verification
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Solution Overview
Problem
Existing multi-party computation techniques do not prevent the server from adapting or changing the algorithm when providing it to multiple clients, which can lead to discrimination and a lack of assurance that clients receive consistent computations, especially when the algorithm is proprietary and sensitive data is involved.
Innovation Solution
A server forms and publishes multiple garbled circuits representing the same function, allowing clients to select one randomly from the list, ensuring the server cannot adapt the algorithm for individual clients, and clients can verify consistency by evaluating multiple circuits, ensuring the same results are produced.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the server provides a single garbled circuit to clients, then the computation efficiency is high, but the server can adapt or change the algorithm for individual clients leading to discrimination
Solution Approach 1:
The server segments the single garbled circuit into multiple identical garbled circuits, each representing the same function. Clients are provided with a subset of these circuits and must evaluate all of them to ensure consistency. This segmentation prevents the server from adapting the algorithm for individual clients while maintaining computational integrity through multiple evaluations.
2Reliability
If the server provides multiple garbled circuits to each client, then clients can verify consistency, but the communication overhead and evaluation time increase
Solution Approach 1:
Instead of requiring clients to evaluate all M garbled circuits, the server provides each client with a subset of n circuits (where n < M). Clients evaluate this smaller subset to verify consistency, which reduces the evaluation time and communication overhead while still providing sufficient verification to prevent algorithm manipulation.
3Loss of information
If the server uses oblivious transfer to protect wire keys, then the secrecy of client inputs is maintained, but the server can still swap wire keys to manipulate client inputs
Solution Approach 1:
The server performs preliminary actions by creating multiple identical garbled circuits with consistent wire keys before providing them to clients. This preliminary setup ensures that even if the server attempts to swap wire keys during oblivious transfer, the multiple circuit evaluations by the client will reveal the inconsistency, preventing manipulation while maintaining input secrecy.
Data Source
AI summary
Various embodiments include a first node for providing a function to a second node for evaluation, the first node configured to form a first plurality of garbled circuits for the function, each circuit being formed from a circuit representing the function and a respective set of wire keys and including one or more logic operations, one or more input wires for inputting data into the circuit and one or more output wires for outputting the result of the function, wherein each respective set of wire keys comprises a respective subset of wire keys for each input wire and each output wire, each subset of wire keys comprising a plurality of wire keys, each wire key in the plurality being associated with a possible value for the wire; and publish a first list of the first plurality of garbled circuits for the function for access by a plurality of second nodes.