Threshold Encryption for Fraud-Resistant Network Measurement
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Solution Overview
Problem
Existing methods for determining aggregated network measurements are vulnerable to fraud and compromise user privacy, as data can be intercepted, altered, or forged, and entities can forge network identities to subvert reputation systems.
Innovation Solution
Implementing a threshold encryption scheme where each client device generates a unique group member key based on network data, allowing decryption only when a threshold number of devices contribute their keys, thereby preventing fraudulent reporting and protecting user privacy without requiring central collaboration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single private key is distributed to each application for reporting network data, then decryption and data aggregation become simple, but the system becomes vulnerable to fraud and identity forgery
Solution Approach 1:
The private key is segmented into multiple shares distributed to different client devices. Each device holds a portion of the key material, and a threshold number of shares are required to reconstruct the group key for decryption. This segmentation prevents single-point compromise and fraud while maintaining operational feasibility through distributed key management.
2Reliability
If client devices communicate directly to collaborate on key generation, then secure decryption is achieved, but bandwidth consumption increases and privacy is compromised
Solution Approach 1:
Each client device independently generates its own group member key using locally available data (network data and application-specific data) without requiring communication with other devices. The devices self-serve the key generation process, and the server aggregates these independent keys to enable decryption, eliminating the need for inter-device communication and reducing bandwidth consumption.
3Reliability
If client devices communicate directly to collaborate on key generation, then secure decryption is achieved, but user privacy is compromised through inter-device communication
Solution Approach 1:
Each client device independently generates its group member key using only local data without communicating with other client devices. This self-service approach ensures that no inter-device communication occurs, thereby protecting user privacy while still achieving secure decryption through the aggregation of independently generated keys on the server side.
4Reliability
If threshold encryption with multiple key shares is implemented, then fraud prevention and privacy protection are improved, but key management complexity increases
Solution Approach 1:
Each client device autonomously generates its group member key using a standardized process based on locally available network data and application-specific data. This self-service key generation simplifies key management by eliminating the need for complex key distribution infrastructure or manual key sharing protocols, while still achieving the security benefits of threshold encryption.
Data Source
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AI summary
Methods, systems, and apparatus, including a method for preventing fraud. In some aspects, a method includes: receiving, from multiple client devices, a measurement data element that includes a respective group member key and a group identifier for a given conversion as a result of displaying a digital component. Each client device uses a threshold encryption scheme to generate, based at least on network data that includes one or more of impression data or conversion data for the conversion, a group key that defines a secret for encrypting the network data and generate, based on data related to the application, the respective group member key that includes a respective share of the secret. In response to determining that at least the threshold number of measurement data elements having the same group identifier have been received, the network data is decrypted using the group member keys in the received measurement data elements.