Chain-of-custody receipts — at1 custody
“Did this data arrive intact, and can we prove it later?” at1 custody append turns every ingested file into one hash-chained appendin a per-site ledger — source, content SHA-256, row count, timestamp. Each receipt links to the one before it, so altering, inserting, or dropping a record breaks the chain. at1 custody verify doesn't just detect tamper — it localizes it to the exact offending record, and at1 custody statusrenders an embeddable “Data custody: verified” line anyone can re-check.
Use it
# append an ingest receipt: one hash-chained entry per file in a per-site ledger
at1 custody append site.ledger --file incoming/cashup_2026-07-14.csv --site branch-07
# re-check the whole chain; on tamper it localizes the offending record (free)
at1 custody verify site.ledger
# the embeddable "Data custody: verified" verifier line + JSON badge for an app UI
at1 custody status site.ledgerWhat it proves
- A receipt per ingest — this exact file, with these exact rows, arrived when it says.
- Tamper localized — not just “something changed” but exactly which record changed; verify points at the first broken link.
- Re-verifiable badge — the status line backs a “Data custody: verified” mark that flips the moment verification fails, so a stale or tampered ledger can't keep showing green.
Honest scope: the receipt proves a file's content and arrival order haven't changed since it was recorded — it does not vouch for what happened upstream before ingest, or that the source itself was honest. The right check is your acceptance test on real data: edit a byte in an archived file and confirm verify names it. Validated on synthetic ingest streams; partner acceptance on live pipelines is pending.
Part of the Regulated Archive family alongside DATABOM and AT-1 Ledger. See the Custody Receipts product page.