The State of ASMap (Bitcoin Core Dev Tech, May 2026)

ASMap (a mapping of IP ranges to autonomous systems, used to harden peer selection against network-level attacks) is now embedded in the latest release — a milestone, with work still ahead. The discussion centered on the collaborative-run process, which gives assurance the embedded map was not fabricated by having multiple independent participants reproduce it. Recent runs showed more non-determinism than expected (one with only 6 of 20 participants matching), and a new web UI now diffs submissions rather than just comparing hashes.

Proposals included a Guix-style attestation process — an asmap.sigs-like signing repo, possibly housed in the existing asmap-data repo — consolidating to a single deterministic encoder rather than maintaining two, adding per-line source annotations for traceability, and building a dashboard to monitor ASMap decay over time. The room weighed whether reproducibility must be exact (the view that emerged: inherent non-determinism is acceptable if it is explainable, "if it's not explainable, it's not shippable") and whether to keep formally releasing tooling versions given that roughly 80% of participants just run master.