ShadowZone: Private Smart Contracts on Public Blockchains

Bitcoin, the first blockchain, was invented for the purpose of allowing individuals to conduct irreversible electronic transactions that do not require the the permission or mediation of any third party, such as banks or governments. Subsequent new blockchains, such as EOS and Ethereum, support “smart contracts” - an arbitrarily user-defined program that controls the distribution of digital currency or assets when certain conditions are met, that is executed by miners and written to the blockchain. While Bitcoin and blockchains like EOS and Ethereum bring tremendous value for users, a major drawback of current blockchain technology is that transaction information is publicly exposed on the blockchain.

ShadowZone is a system that utilizes hardware enclaves to ensure the confidentiality of smart contracts. ShadowZone writes the contract’s resulting transaction data to the public blockchain, but not the contract itself; the content of the contract remains private, cryptographically secured, only viewable by participants in the contract.

ShadowZone is a secure, private, off-chain platform for the execution of smart contracts, using a Trusted Execution Environment (TEE) for storage and execution of contracts while requiring that only the verification be written to the public blockchain. A protocol token - SZT - is an incentive that “workers” (the equivalent of miners) can earn by providing correct, confidential computations for users.

ShadowZone is first being developed for EOS, but its modular design allows it to be easily integrated into other compatible blockchains, such as Rootstock (RSK), Ethereum (ETH), and many more. ShadowZone is open source and we welcome collaboration with anyone who wishes to achieve the privacy and scalability improvements that this new technology can provide.

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Use Cases

Example 1: Secure Voting

An EOS smart contract can be used by a group of participants to create a vote together. The usefulness of secure blockchain voting has long been appreciated, but ShadowZone can make it even better by providing major improvements in privacy. The entire details of the vote contract are hidden to everyone except the participants, individual votes are hidden to all but the voter, and all voters can check the current vote totals at any time. In the ShadowZone network, workers execute the contracts but cannot see any of the details.

Example 2: Private Auctions

Smart contract capabilities of the EOS blockchain enable participants to conduct auctions, where bidders’ money is returned to them if it isn’t the winning bid. ShadowZone enhances blockchain auctions by making them private - participants’ bid amounts are concealed from other bidders, even after the auction is concluded and their return transaction is executed. The details of the auction contract are known only to the participants, the bid amount is known only to the bidder, and only the transaction data is written to the blockchain.

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The core members of the ShadowZone development team are from top academic institution in Asia.