license: cc-by-4.0
pretty_name: Software Heritage content bloom filters
Software Heritage content membership filters
DCSO-format bloom filters over the content hashes of all 29,283,034,124
content blobs in the Software Heritage
archive (graph dataset export 2026-06-04, content table), one
filter per hash scheme, false-positive rate p = 0.0001 each:
| file | keyed on | key encoding |
|---|---|---|
swh.sha256.bloom |
sha256 | lowercase hex |
sha1_git is the git blob id — membership testing straight from a git
object id, no file bytes needed.
Ask "has SWH archived this content?" without touching the rate-limited
API — then confirm hits at
https://archive.softwareheritage.org/api/1/content/<scheme>:<hex>/.
Built for hashdex (hdx scan),
readable by any DCSO/hashlookup-compatible bloom implementation
(header: LE u64 version, n, p-bits, k, m, N; then bit array;
membership = FNV-1 64 mod 2^64-87, k rounds of wrapping multiply by
18446744073709550147 mod 2^64-87, bit index mod m).
Derived from the Software Heritage graph dataset (CC-BY 4.0, attribution: Software Heritage). See their dataset docs.