Enhanced Privacy with Blockchain-based Storage for Data Sharing.

The core concept of electronic money is blockchain, which can be regarded as a decentralized database. It is a decentralized storage service that does not rely on third-party storage. It records each transaction information on the block. Related applications include electronic ledgers, which further extend smart contracts. In storage, not only record transactions, but the extended smart contract can be used in medical treatment, recording the patient's medical records. However, there is a need for privacy in medical records, and it must be able to be accessed by appropriate people in accordance with the authority. So it needs a technology like Enigma to achieve it. Enigma uses multi-party computation (hereinafter referred to as MPC) and distributed hash-table (hereinafter referred to as DHT) technology, combined with the blockchain to divide the data to be stored into public blocks and private parts The blockchain has an existing way of computing and storing, and private data is Enigma's method of computing and storing by using the method called Off-Chain. Only authenticated users can access private data. However, many applications have the need for group sharing and decentralized records. This study uses Enigma to encrypt the data that requires privacy using the key of the encrypted file and then uploads it to DHT for storage, so that the owner of the private data can further share the data securely.