Combining KZG and erasure coding
The first episode in our Hitchhiker’s Guide to Subspace series discusses polynomial PoRs for Subspace v2 and the combination with KZG commitments. It overviews the trade-offs for different forms of Reed-Solomon (RS) erasure codes and Kate-Zaverucha-Goldberg (KZG) commitments, including their benefits and challenges. The article also introduces KZG polynomial commitments, proof batching schemes for KZG, and their use cases in distributed data storage. I strongly recommend reading the first episode for context.
It is crucial for Subspace Archiving to leverage KZG commitment and erasure coding to guarantee that the history pieces were erasure coded correctly and are recoverable on request.
In this article, I outline our lessons learned from combining RS and KZG and provide an overview of existing schemes, some described in research papers and others currently used by other teams. The insights in the first half of this article will come in handy for understanding the constructions in the second half.