  In the age of Big Data, releasing protected sensitive data at a future point
in time is critical for various applications. Such self-emerging data release
requires the data to be protected until a prescribed data release time and be
automatically released to the recipient at the release time, even if the data
sender goes offline. While straight-forward centralized approaches provide a
basic solution to the problem, unfortunately they are limited to a single point
of trust and involve a single point of control. This paper presents
decentralized techniques for supporting self-emerging data using smart
contracts in Ethereum blockchain networks. We design a credible and enforceable
smart contract for supporting self-emerging data release. The smart contract
employs a set of Ethereum peers to jointly follow the proposed timed-release
service protocol allowing the participating peers to earn the remuneration paid
by the service users.We model the problem as an extensive-form game with
imperfect information to protect against possible adversarial attacks including
some peers destroying the private data (drop attack) or secretly releasing the
private data before the release time (release-ahead attack). We demonstrate the
efficacy and attack-resilience of the proposed techniques through rigorous
analysis and experimental evaluation. Our implementation and experimental
evaluation on the Ethereum official test network demonstrate the low monetary
cost and the low time overhead associated with the proposed approach and
validate its guaranteed security properties.
