A Sidechain corresponds to a second blockchain that allows tokens and other digital assets from one blockchain to be used securely in a separate blockchain, and then brought back to the original blockchain if necessary.
Sidechain functionality offers tremendous potential to enhance the capabilities of existing blockchains. Sidechains can set up their own validation rules, and they are responsible for their own security. Bidirectional anchoring allows for the interchangeability of assets at a predetermined rate between the parent blockchain and the sidechain.
Several cryptocurrencies use this principle, such as Ardor, Stratis and Lisk. Alternatives to sidechains are also being developed, such as Lightning Network for Bitcoin and Raiden for Ethereum.
