Retrievable archive coverage for every key range

Establish how to keep every key range retrievable in an archive supporting BUD and SuperBUD historical-read certificates.

Background

BUD historical reads depend on continued availability of records, span maps, Merkle material, attestations, and committee-transition evidence. The paper treats replication, sharding, payments, and availability bonds as deployment choices, but does not resolve how archival systems should provide reliable coverage for all key ranges.

The unresolved problem is therefore an operational and incentive-design question: construct an archive or availability mechanism that ensures every key range needed for historical queries remains retrievable.

References

Replication, sharding, payments, and availability bonds are deployment choices; keeping every key range retrievable remains open.

— You've Got a BUD in Me: Authenticated Reads from Per-Block Write Logs  (2609.11251 - Ranchal-Pedrosa et al., 10 Sep 2026) in Appendix, Section “Deployment,” paragraph “Archive incentives” (label app:deployment)