On the tracking of sensitive data and confidential executions

Abstract

The production of large amounts of sensitive data raises growing concerns on confidentiality guarantees. Considering this, it is natural that data owners have an interest in how their data are being used. In this work, we propose Data aNd Application Tracking (DNAT), a trustworthy platform for tracking the executions of applications over sensitive data in untrusted environments. For traceability purposes, we use blockchain and smart contracts, and to guarantee execution confidentiality and, especially, enforce that operations are appropriately logged in the blockchain, we use Intel SGX. Experiments show that tracking costs on Ethereum varies from 1 to 61 cents of a US dollar, depending on the operation and urgency for consolidation. The time cost of confidential execution is associated with the SGX overhead. It increases non-linearly initially but has a linear growth rate when data and application size gets much higher than the available enclave page cache ( 93 MB).