Four-party computation type conversion using unified share formats
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Solution Overview
Problem
Current four-party computation methods face challenges in efficient type conversion and dishonesty detection, particularly when using 2-out-of-4 replicated secret sharing, which complicates the execution of mixed circuits and increases communication costs.
Innovation Solution
An information processing apparatus and method that includes a basic operation seed storage, reshare value computation, and share construction parts to generate random numbers, compute reshare values, and construct shares for type conversion, enabling efficient type conversion in four-party computation while detecting dishonesty.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If 2-out-of-4 replicated secret sharing is used for type conversion, then security against malicious adversaries is improved, but communication cost increases
Solution Approach 1:
The protocol segments the type conversion process into distinct phases: correlation setup, share conversion, and verification. Each phase handles specific tasks independently, allowing efficient communication patterns to be established and reused across multiple operations, thereby reducing overall communication cost while maintaining security
Solution Approach 2:
The protocol performs preliminary actions by pre-establishing correlated random values and verification keys before the actual type conversion. This preparation phase enables subsequent conversions to proceed with minimal communication overhead, as the expensive setup is done once and reused
2Adaptability or versatility
If type conversion is performed in four-party computation, then adaptability for mixed circuits is improved, but device complexity increases
Solution Approach 1:
The protocol implements universal share conversion mechanisms that can handle multiple share formats (additive, multiplicative, and mixed) through a unified framework. The same core protocol structure accommodates different circuit types (arithmetic and logic) by adjusting parameters rather than requiring separate protocols, thereby reducing device complexity while improving adaptability
Solution Approach 2:
The protocol achieves adaptability for mixed circuits by changing parameters such as the number of parties, share representation, and operation types rather than altering the fundamental protocol structure. This allows a single device implementation to handle diverse computational tasks with minimal reconfiguration
3Reliability
If dishonesty detection is enhanced, then reliability is improved, but communication overhead increases
Solution Approach 1:
The protocol incorporates feedback mechanisms where parties verify each other's computations and share consistency information. Verification results feed back into the protocol to either confirm successful conversion or trigger corrective actions, enabling reliable dishonesty detection through efficient use of communication channels rather than increasing overhead
Data Source
AI summary
The information processing apparatus comprises a basic operation seed storage part, a reshare value computation part, and a share construction part. The basic operation seed storage part stores a seed for generating a random number used when computation is performed on a share. The reshare value computation part generates a random number using the seed, computes a share reshare value using the generated random number, and transmits data regarding the generated random number to other apparatuses. The share construction part constructs a share for type conversion using the data regarding the generated random number and the share reshare value received from other apparatuses.