Evaluate and Guard the Wisdom of Crowds: Zero Knowledge Proofs for Crowdsourcing Truth Inference

Due to the risks of correctness and security in outsourced cloud computing, we consider a new paradigm called crowdsourcing: distribute tasks, receive answers and aggregate the results from multiple entities. Through this approach, we can aggregate the wisdom of the crowd to complete tasks, ensuring the accuracy of task completion while reducing the risks posed by the malicious acts of a single entity. However, the ensuing question is, how can we ensure that the aggregator has done its work honestly and each contributor's work has been evaluated fairly? In this paper, we propose a new scheme called $\mathsf{zkTI}$. This scheme ensures that the aggregator has honestly completed the aggregation and each data source is fairly evaluated. We combine a cryptographic primitive called \textit{zero-knowledge proof} with a class of \textit{truth inference algorithms} which is widely studied in AI/ML scenarios. Under this scheme, various complex outsourced tasks can be solved with efficiency and accuracy. To build our scheme, a novel method to prove the precise computation of floating-point numbers is proposed, which is nearly optimal and well-compatible with existing argument systems. This may become an independent point of interest. Thus our work can prove the process of aggregation and inference without loss of precision. We fully implement and evaluate our ideas. Compared with recent works, our scheme achieves $2-4 \times$ efficiency improvement and is robust to be widely applied.