Suddan N Shanmugasundaram

Of course, this has consequences on what we can store on a blockchain. Storing personal data on a blockchain is not an option anymore according to GDPR. A popular option to get around this problem is a very simple one: You store the personal data off-chain and store the reference to this data, along with a hash of this data and other metadata (like claims and permissions about this data), on the blockchain. To see how this works in a permissioned blockchain, consider the picture below. There are 2 companies (called BlueCompany and GreenCompany) with each there own back-ends, both connected to a blockchain.

Use chaincode to create decentralized applications that manage the lifecycle of one or multiple types of business contracts, and let the end users instantiate instances of contracts within these applications. [More Efficient]

In Hyperledger Fabric, chaincode is the ‘smart contract’ that runs on the peers and creates transactions. More broadly, it enables users to create transactions in the Hyperledger Fabric network’s shared ledger and update the world state of the assets.