Secret Contract - Private Smart Contract

Background

Blockchain stores all data publicly on it while it offers a open ledger for simple blockchain like Bitcoin, it might not be suitable to show every data publicly for more complicated application.

Using smart contracts to interact with the blockchain and other users could expose a lot of sensitive user data in current model. Completely open blockchain is not a practical environment when users have submit sensitive data like bank info and history to the smart contracts.

Some dApp provider keeps the actual computation of eligibility centralized, in order to limit the exposure of the sensitive data to the provider itself. However, the dApp retains all of the weaknesses of centralized applications like single point of failure and easy target of attack.

Enigma Secure Contract

The Enigma team design Secret Contract, the smart contract that protects the blockchain correctness through distributed consensus while executed privately. Secret contract can hide the data completely from the nodes. The nodes can execute the contract and receive the eligibility result without being able to observe the user’s transactions.

Unlike using Zero-knowledge proofs which a party with access to the data can prove a claim to others without revealing the data to them, secret contracts usually have to outsource computations to execute the contract involving multiple parties that there isn’t a single party can be trusted to know all of the data.

For secret contracts, secure computation is used to enable computing over encrypted data. Secure contracts are able to hide its exact data from the nodes in the network while preserving the ability to be executed and validated.

Development

In the first Enigma network release, it will make use of TEEs ( Trusted Execution Environments), the secure area inside any processor to conceal data from the network. In the second release, they will introduce secret contracts that are based on a purely cryptographic solution called secure Multi-Party Computation (MPC).

Recently, Enigma has partnered with Intel on research and development efforts to advance development of privacy preserving computation technologies utilizing Intel technology to building a private, scalable, secure solution to power the real world daly usage of smart contracts with personal data.

References

https://blog.enigma.co/defining-secret-contracts-f40ddee67ef2
https://blog.enigma.co/why-enigmas-privacy-protocol-will-power-our-decentralized-future-aedb8c9ee2f6
https://blog.enigma.co/announcing-enigmas-collaboration-with-intel-43bbf73a86a7