EIP-7916: SSZ ProgressiveByteList

zsfelfoldi · March 25, 2025, 10:11am

Add EIP: SSZ ProgressiveByteList

ethereum:master ← etan-status:sz-progressivebytelist

opened 03:47PM - 24 Mar 25 UTC

Move SSZ ProgressiveByteList to its own EIP so that it can be worked on independ…ently of the eth_getLogs filter usage. Plans are to work with @wemeetagain to generalize it beyond byte lists, and to simplify the parameters with `CAPACITY = unbounded` as well as `COMMON_RATIO = 4`. That way, in EIPs such as EIP-6404 and EIP-6466 it is no longer necessary to define arbitrary bounds to byte lists, and in consensus we can use such an `UnboundedList[T]` construct to replace proposer / attester slashing lists (with a shared maximum allowed len), and could use it for attestations list that keeps changing across forks. First step is to move this out to its own EIP with Zsolt as author, then do the followup work with me and @wemeetagain in separate PRs.

This EIP introduces a new Simple Serialize (SSZ) type to make List[T, N] with large capacities N more efficient in cases where the list is much shorter than the capacity.

etan-status · June 24, 2025, 12:28pm

Added ProgressiveBitlist
Tree now grows to left instead of right
Fixed incorrect Bitvector notion in graphic: Unused chunks are padded with 0 chunks instead of default(T) chunks.
Simplified Merkleization code

etan-status · July 31, 2025, 10:27am

Started an implementation tracker: https://pureth.guide/implementations-ssz/