@kashscript/whiffin — the Settlement Protocol (rail-agnostic)

Crypto is one optional rail, never a requirement. Commercial (SSLA Schedule B). Where money moves, ventures consume Whiffin and never reach for raw trade-sdk.

Built in phase M4 of the protocol Manifestation (ADR-0016). Purpose-bound mandates + signed receipts + reconciliation reports on @kashscript/attest; payment rails (Raast/EMVCo/Safepay/SoftPOS) as adapters. The generic machinery is derived from the Duedale grant/report/rails seeds; SegmentPolicy content, DD_* mapping, funder/vendor UI, and the demo's SIMULATION posture stay venture-side. Full contract: specs/whiffin.md.

Mandate core — W3C VCs with AP2 semantics

A purpose-bound grant is an AP2 Intent Mandate: a fixed max amount, a purpose lock, an allowed-vendor set (Merkle root), an expiry/TTL, and a single-use nonce — pre-authorizing redemption.

import { issueGrant, markDelivered, redeemGrant, InMemoryGrantLedger, InMemoryNonceStore } from "@kashscript/whiffin/mandate";
import { toMandateCredential, verifyMandateCredential } from "@kashscript/whiffin/credential";

const { signed, record } = await issueGrant(req, program, operatorPriv, ledger);
const vc = toMandateCredential(signed, { issuer: operatorDid });   // W3C VC 2.0 + AP2 Intent Mandate
await verifyMandateCredential(vc, operatorPub);                    // proof = the kash-grant-v1 signature

• Lifecycle — issueGrant · markDelivered · redeemGrant, with GrantLedger/NonceStore interfaces (+ in-memory reference impls).
• Policy gate (@kashscript/whiffin/policy) — a config-driven, ordered set of named checks (signature · beneficiary binding · purpose · expiry · vendor Merkle inclusion), nonce burned LAST. Zero segment branching — reads fields only; errors are neutral WhiffinPolicyError codes.
• Credential (./credential) — Intent Mandate (grant) + Cart Mandate (offer→receipt→dispute) as W3C Verifiable Credentials; the proof embeds the existing Kash-Event Ed25519 signature (no new crypto).

Rails (@kashscript/whiffin/rails)

emvco (MPM v01 + CRC-16/CCITT-FALSE), raast (P2M QR + shared-secret verifier), safepay (HMAC verifier), softpos (bridge loader + camera scanner + reader guard), partner-ledger (interface + SimulationPartnerLedger — every result labelled simulation: true), and chain (interface + not-wired stub; the EVM/Solana impl is venture-wired via trade-sdk, artifacts guard applies).

Reconciliation (@kashscript/whiffin/report)

The every-rupee-style report — a pure projection (per-grant lifecycle · vendor breakdown · totals) + a render-time SHA-256/JCS hash-chain + a kash-report-v1-signed envelope. Generalized (simulation / settled / refunded / disclaimers / envelope-typ injected). A report generated here re-verifies under attest's verifyDuedaleReport when the venture-branded envelope type + genesis label are passed. Reconciliation invariant: issuedPaisa === redeemedPaisa + unspentPaisa.

Status

0.x — the API stays 0.x until duedale-angel's terminal + /report flows swap onto the published package (consumer-as-acceptance, ADR-0016). The runtime license assertion + registry tier mapping land in M6. Depends on @kashscript/identity-core + @kashscript/identity-zkp (/merkle) + @kashscript/attest.

Commercial — SSLA Schedule B; see LICENSE.