Polytope Labs Research
Blockchain research at the forefronts of the decentralization revolution.
I explore the technical definition of consensus proofs, review their vulnerabilities, and examine the mitigations for these vulnerabilities. I then show how these mitigations enable consensus proofs to be safely used on-chain, allowing for the first-of-its-kind byzantine fault-tolerant cross-chain bridges.
State proofs are a critical primitive of the blockchain stack that enable things like trustless bridges, off-chain light clients that can access on-chain data in a permissionless and secure manner as well as modular blockchains architectures where the execution layer can be decoupled from the consensus layer.

Merkle mountain ranges are an improvement over conventional merkle trees for growing, potentially unbounded lists. Where conventional merkle tree constructions over growing lists prove very inefficient to compute, as all nodes in the tree must be recomputed. Merkle mountain ranges amortise this cost by growing subtrees incrementally and merging subtrees at the same height, rather than growing the full tree.

This technical specification assumes that you’re already aware of the sync committee protocol introduced in the altair, the first hard fork of the ethereum beacon chain. If not, tl;dr: The original attestation protocol unfortunately did not include succint BLS public key aggregation, which would’ve made it cheap to verify by light clients given that there are now almost 500k authorities actively validating blocks on the beacon chain.