(2026-04) Efficient Merkle-Tree Consistent Accumulator
2026-04-06
A consistent accumulator computes a digest for a dynamically-growing set of elements, with a proof of consistency of the new digest with the previous digests. Consistent accumulators are in wide use, in particular, by Certificate Transparency (CT), which is part of the Web PKI, and in blockchains.
We present a significantly more efficient design for a consistent accumulator. Our design is compatible with the CT specifications; similarly to the widely-used, open-source CT implementation, it uses a Merkle tree, but much more efficiently. We provide open source implementation, security analysis and experimental evaluation showing the performance improvements.