Setchain algorithms for blockchain scalability

Abstract

Blockchain scalability remains a longstanding obstacle to its broader adoption. To mitigate this limitation, numerous approaches have been proposed to improve blockchain throughput and efficiency. One such approach is Setchain, a reliable distributed object that improves scalability by relaxing the strict total-order requirement among transactions. Setchain arranges elements as an ordered sequence of sets, called epochs. Elements inside an epoch have no internal order, while epochs themselves are totally ordered. In this work, we introduce and evaluate three Setchain algorithms built on top of a block-based ledger. Vanilla is a straightforward baseline implementation. Compresschain groups elements into batches and compresses them before appending them as epochs on the ledger. Hashchain instead maps each batch to a fixed-length hash, which is then appended as an epoch in the ledger. This design requires Hashchain to rely on a distributed service to retrieve the batch contents corresponding to a given hash. To enable light clients to safely interact with a single server, the proposed algorithms store epoch-proofs within the Setchain. An epoch-proof is the hash of the epoch, cryptographically signed by a server. A client can verify the correctness of an epoch with epoch-proofs, where f is the maximum number of Byzantine servers assumed. We implement all three Setchain variants on the CometBFT blockchain application platform and deploy them as Docker-based nodes in a cluster. We evaluate performance under multiple settings using clusters with four, seven, and ten servers. The results indicate that the Setchain algorithms achieve throughput orders of magnitude higher than that of the underlying blockchain, while reaching finality with latency under 4 s.