OKVS-Based Multi-Stage OPRF Against Random Substitution Attacks

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Solution Overview

Problem

Existing oblivious pseudo-random function (OPRF) protocols based on oblivious key-value store (OKVS) are vulnerable to random substitution attacks, allowing malicious receivers to obtain unauthorized information, and result in a sharp increase in communication volume.

Innovation Solution

A method involving multiple applications of OPRF protocols using OKVS, with configured bit counts and probability bounds to prevent information leakage and reduce communication, including a first and second OPRF protocol with optimized bit counts and probability bounds to minimize information exposure and communication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a single OPRF protocol is used, then the protocol is simple to implement, but it is vulnerable to random substitution attacks and allows information leakage

Engineering Contradiction:

Improvesecurity against random substitution attacksVSAvoidprotocol complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the single OPRF protocol into multiple sequential OPRF protocols (first OPRF protocol and second OPRF protocol). Each protocol handles a specific stage of the computation, with the output of one protocol serving as input to the next. This segmentation prevents random substitution attacks by ensuring that intermediate results from one protocol cannot be substituted into another, while maintaining overall system security.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary computations in the first OPRF protocol before executing the second OPRF protocol. The first protocol pre-computes certain values that are then used as inputs to the second protocol, ensuring that sensitive operations are performed in a controlled sequence where intermediate results cannot be exploited by malicious receivers.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If bit counts are increased to prevent information leakage, then security is improved, but communication volume increases sharply

Engineering Contradiction:

Improveinformation leakage preventionVSAvoidcommunication volume

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent dynamically adjusts the bit counts for different protocols based on the specific security requirements and communication constraints. The first OPRF protocol uses a first bit count configured according to the probability bound for information leakage, while the second protocol uses a second bit count optimized for its specific computational needs. This dynamic configuration allows the system to achieve security goals without uniformly increasing communication volume throughout the entire protocol execution.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of bit count between different protocol stages. By configuring the first bit count for the first OPRF protocol and the second bit count for the second protocol according to their respective probability bounds, the system optimizes the balance between information leakage prevention and communication efficiency at each stage rather than using a fixed high bit count throughout.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If multiple OPRF protocols are applied sequentially, then security against attacks is improved, but communication overhead increases

Engineering Contradiction:

Improveattack prevention capabilityVSAvoidcommunication overhead

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent merges the outputs of the first OPRF protocol with the inputs of the second OPRF protocol in a coordinated manner. The second key-value pair uses the first PRF data as its key, creating a chained structure where the computational work and communication are integrated across protocols rather than being completely separate. This merging approach allows the system to achieve enhanced security through multiple protocols while minimizing redundant communication.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS20260067065A1Method for multiple applications of oblivious pseudo-random function protocol between receiver and sender based on oblivious key-value store algorithm, and device using same

Publication Date: 2026.03.05 SAMSUNG SDS CO LTD

AI summary

The present disclosure relates to a method for multiple applications of an oblivious pseudo-random function protocol between a receiver and a sender based on an oblivious key-value store algorithm, and a terminal device using the same, and a method for multiple applications of an oblivious pseudo-random function protocol according to an embodiment of the present disclosure may include the steps of: inputting, by the receiver, a first key-value pair between target data and hash data corresponding to the target data to receive first PRF data generated according to a first OPRF protocol based on the OKVS; and inputting, by the receiver, a second key-value pair between the target data and the first PRF data to receive second PRF data generated according to a second OPRF protocol based on the OKVS.