Rollup Protocol

Optimistic Rollups

Caldera Chains utilize a technology called "Optimistic Rollups" which allows them to leverage the security of another blockchain, known as the parent chain, without needing to establish their own consensus mechanism. This approach allows Caldera chains to benefit from the established security of the parent chain while still providing the benefits of increased scalability and efficiency.

Fault Proofs

In an Optimistic Rollup, the state of the chain is recorded on Ethereum, but without providing direct evidence of its validity. Instead, these state commitments are considered provisional for a specific period of time, called the "challenge window." If a proposed state commitment goes unquestioned for the duration of the challenge window, it is considered final and smart contracts on Ethereum can safely accept withdrawal proofs about the state of the chain based on that commitment.
In the event of a challenge, the commitment can be invalidated through a process known as "fault proof." If a challenge is successful, the commitment is removed from the StateCommitmentChain and replaced by a new proposed commitment. However, it's important to note that a successful challenge does not roll back the chain, but only the published commitments about the state of the chain. The ordering of transactions and the state of the chain remain unchanged by a fault-proof challenge.

Learn More about Rollups

An Incomplete Guide to Rollups
From Ethereum founder Vitalik Buterin's blog