EPT: Enhancing User Transparency for Confidential Smart Contract

Abstract

In the burgeoning era of digital finance, ensuring user privacy protection within blockchain systems has become a crucial concern. Despite this, existing privacy enhancement methods often lack user-friendliness, as they necessitate users to navigate complex protocols, thereby raising the barrier to entry. This paper introduces EPT, an efficient framework that not only addresses the user privacy concern but also enhances usability. Our method allows users to interact with confidential smart contracts deployed in a Trusted Execution Environment (TEE) by sending private transactions directly to the blockchain. We devise a secure TEE attestation and data privacy scheme for secure private transactions, even when users interact indirectly with the TEE. Further, we utilize a robust data acquisition approach for inputting valid and fresh private transaction-related data into the TEE. Our extensive evaluations demonstrate that EPT can deliver confidential transactions at a gas cost comparable to that of non-confidential block transactions, with a high throughput of 2, 715 tx/s, and an end-to-end latency of around 12 seconds.