Blockchain Patterns, Mechanisms, Models, Metrics > Integrity and Validation Patterns > Sidechain
How can a blockchain application user carry out an off-chain transaction without compromising the integrity of the main chain?
When a blockchain application user carries out a transaction with another user outside of the blockchain network, the transaction cannot be fully validated or subjected to consensus within the blockchain application. If such transactions are written to the main chain and then turn out to be invalid, it can compromise the integrity of the distributed ledger.
The blockchain application allows off-chain activity to be recorded outside of the main chain until it can be safely determined that the associated records are valid.
A sidechain is created and linked to the main chain, but comprised of blocks that are separated until it is deemed safe to merge them with the main chain.