Timed release of data is a classical problem. Timed data release ensures that protected data remains secure and undiscovered until a prescribed release time and gets automatically released at the release time. Examples of applications requiring timed data release include secure auction systems (bidding information needs protection until all bids arrive), copyrights-aware data publishing (data is automatically released when the copyright expires) and secure voting mechanisms (votes are not allowed to be accessed until the end of the polling process). However, such a data release primitive inevitably exposes itself to security threats. A successful release-ahead attack prematurely releases the protected data before the prescribed release time and a successful drop attack destroys the protected data altogether. Therefore, designing a highly secure and attack-resilient approach is critical to supporting such services for timed release of data. This project takes the first step towards developing highly decentralized solutions for supporting timed release of data using Blockchain-based mechanisms. At a high-level, it consists of a suite of novel protocols enforced by smart contracts. Peers on the blockchain network are incentivized to follow the protocol to take charge of protecting, transferring, and automatically releasing the data. This research further augments the timed data release techniques with mechanisms for decentralized timed transactions that enable scheduling of transaction functions without revealing the function inputs prior to the execution time. By incorporating the timed data release as well as the timed transaction techniques, the proposed solutions show a promising support for applications requiring privacy-preserving and reliable timed transaction service (e.g., absentee voting service in blockchain-based e-voting platforms).

This project aims to build the next generation decentralized infrastructures for supporting secure timed data release and timed execution of transactions that do not involve a single point of trust. A key aspect to this model is a suite of novel secure data management techniques without a single point of trust, which allows the data to be published at a future time point (i.e., the data becomes available at the release time and prior to the release time, it remains undiscovered and unavailable). The timed-release mechanisms route the protected data within the timed data release system in a deterministically pseudo-random manner, enabling it to automatically appear at the release time. The proposed techniques provide security guarantees by designing a monetary incentive mechanism enforced by the blockchain to reward honest peers and penalize violators of the protocol. The mechanisms are designed to protect against both rational and malicious peers in the system. A key objective of the system design is to minimize the gas cost of executing the timed data release and timed execution protocols while maintaining high scalability and availability. The project demonstrates the use of timed data release and timed execution features by developing a suite of decentralized applications using the proposed techniques. We implement the proposed mechanisms using the contract-oriented programming language, Solidity and evaluate the techniques on the Rinkeby Ethereum test network.

The project aims to produce the techniques, algorithms, design and implementation to enable timed release of data and timed execution in decentralized blockchain platforms. Research results from the project will be integrated into the security track courses at the University of Pittsburgh. The project will engage the security track students in the proposed research and development activities. A new doctoral seminar course focusing on the state-of-the-art blockchain research as well as practical decentralized application development is developed as part of the project. New teaching materials related to blockchains will be incorporated as introductory modules for high school students.