Certified Variables

Why do you trust data obtained from a blockchain? The answer lies in the consensus protocol, which ensures that all transactions and the subsequent changes to smart contract states are correct, as long as the underlying trust assumptions hold. However, verifying correctness based on the consensus protocol can be tedious. A client has to download and validate the blockchain data. Even with more efficient mechanisms like Bitcoin's SPV or Ethereum's light clients, clients still have to perform significant work, such as downloading and validating block headers. This makes it challenging for applications with limited uptime and resources, such as mobile or web applications, to operate on blockchain data without relying on centralized intermediaries.

The certification feature in BigFile is exposed to cubes through certified variables. From an application perspective, certified variables can be set during an update call to a cube, when the cube changes its state during a transaction that has gone through consensus.