dig-offers

The DIG Network canonical Chia offers expert crate: a pure, key-free, network-free SpendBundle-builder for Chia offers (settlement per CHIP-0023/CHIP-0024) over any asset (XCH / CAT / NFT).

dig-offers constructs the exact CoinSpends for every offer operation and reports the exact signatures a caller must produce. It never holds a secret key, never signs, and never touches the network. The consumer signs the reported messages, assembles/combines the SpendBundle, and broadcasts.

Scope

make — build a one-sided offer: OFFER assets (spent into the settlement puzzle) and REQUEST assets (asserted, paid to the maker) — returns the unsigned offered coin spends + the requested-payment metadata; the caller signs, then dig-offers assembles the offer1… string.
take — accept an offer: build the taker's counter-spends (fund the requested side, claim the offered coins), report required signatures, then combine with the maker's signed half.
combine — merge multiple compatible offers into a single settlement.
cancel — reclaim the offered coins of an outstanding offer back to the maker.
summarize / inspect — decode an offer1… string into a two-sided summary (offered vs requested, arbitrage, royalties) without committing.
offer id — stable, deterministic identifier for persistence + dedup.

The two-phase flow (make / take)

Building and assembling are split so the caller signs BETWEEN them, in ONE shared SpendContext:

make:  make_build(ctx, offered, requested, fee) -> UnsignedMake
       required_signatures(&unsigned.coin_spends, agg_sig_me)  // caller signs
       make_assemble(ctx, signed_bundle, requested_payments, requested_asset_info) -> "offer1…"

take:  take_build(ctx, offer1_str, funds, fee) -> UnsignedTake
       required_signatures(&unsigned.coin_spends, agg_sig_me)  // caller signs (taker half only)
       take_combine(unsigned.offer, signed_taker_bundle) -> SpendBundle  // atomic settlement

The two phases of each flow MUST share the same SpendContext: a parsed/requested NFT carries an allocator-relative metadata pointer that only survives in that context. take_combine and combine outputs are allocator-free and safe to hand out.

Custody model

Identity-agnostic (#908): builders take public inputs only — puzzle hashes, asset ids, coins with lineage proofs, and PublicKeys (owner_keys: IndexMap<Bytes32, PublicKey>). The crate BUILDS unsigned spends and REPORTS the required signatures; the caller SIGNS. No function accepts, stores, derives, or returns a secret key, and the crate never produces a BLS signature or performs I/O. See SPEC.md for the normative contract.

Dependency position

dig-offers sits above the 00-foundation layer: it consumes dig-cat and dig-nft (both 00-foundation) and chia-wallet-sdk, and is consumed by higher-level aggregators (e.g. dig-wallet-backend). All dependencies are crates.io releases (no git deps).

License