A reconciliation you can prove
Seal two archives — a bank statement and a POS tape — and join them under a hashed rule set. at1 reconcile emits a signed certificate: the matches, and the residuals (the genuinely unmatched rows on each side). An independent auditor re-confirms the verdict from the certificate alone— no raw rows, no our binary — and the certificate proves the matched and residual rows together account for every row. A silently-dropped unmatched line is made cryptographically impossible.
- partition
- matched ∪ residual = the whole archive — a dropped row can't hide
- cert-only
- an auditor re-verifies the verdict without the raw rows or our binary
- N:M
- one deposit ↔ many tickets: deterministic batch settlement, not guesswork
- residual list
- the attested unmatched rows — the thing the audit shop buys
Reconcile, then hand off the receipt
at1 reconcile run bank.csv pos.csv --rules R.json -o cert.json --residuals-out X.csv # 7 match group(s), 4 residual(A) + 4 residual(B); k_open=8; root_A=b9e09a9d... # self-verify: VERIFIED — 7 match group(s) spot-audited under R at1 reconcile verify cert.json # free, no raw rows, no account # VERIFIED: 7 match group(s), 4 residual(A) + 4 residual(B); 7 spot-audited under R # attested residual list: 4 on side A, 4 on side B
Money is carried as integer cents and dates as day-ordinals, so the certificate’s hash is byte-stable and re-running the same inputs reproduces the same certificate exactly.
No row can vanish
The certificate proves the matched rows and the residual rows together partition the whole archive, disjoint, per side. This guarantee is unconditional— it is the property three broken layers of “unmatched” can never satisfy.
Matches on amount + date
By default it pairs on amount and date— because a bank statement and a POS tape share no reference strings (that absence is why the problem exists). Shared tokens are an optional booster. One deposit against many tickets: the N:M matcher groups rows and settles a group only when its sums agree within tolerance and dates fit the window — deterministic, reproducible, documented.
Honest scope
Membership, partition-completeness and residual authenticity are cryptographically unconditional. Match-honesty is a probabilistic Fiat-Shamir spot-audit(k challenge-selected matches re-checked; the prover can’t cherry-pick which). This is notzero-knowledge — a true-ZK match proof is on the roadmap.
Part of the Regulated Archive & Trust family alongside AT-1 Ledger and Regulated Archive. “Verified” means integrity, partition-completeness and reproducibility — not confidentiality of the matched rows, which the spot-audit reveals in part by design.