Glossary

Glossary

One line each, for both users and developers.

• Atomic swap — a cross-chain trade where either both legs complete or neither does; no third party ever custodies the coins.
• HTLC — Hash Time-Locked Contract; the v1 swap output, spendable by a hash preimage before a timelock or refunded after it.
• Adaptor signature — a signature missing one secret offset; revealing the offset (the adaptor secret) completes it and, on-chain, leaks that secret to the counterparty. Basis of the v2 swap.
• MuSig2 — a 2-round Schnorr multisignature scheme; v2 legs are co-signed 2-of-2 with it.
• Taproot / tapleaf — Bitcoin's Schnorr+Merkle output type; v2 uses a key-path spend for the cooperative redeem and a tapleaf script for the timelock refund.
• CLTV — OP_CHECKLOCKTIMEVERIFY; the opcode enforcing a timelock refund branch.
• MTP — Median Time Past; the block-time measure used to decide when a timelock has matured.
• RBF — Replace-By-Fee; rebroadcasting a transaction with a higher fee to speed confirmation.
• CPFP — Child-Pays-For-Parent; attaching a higher-fee child to bump a stuck parent (used to speed the un-bumpable v2 redeem).
• Preimage — the secret s whose hash H locks a v1 HTLC; revealing it claims the leg and links the two sides.
• Maker / taker — the maker posts an offer and funds first; the taker accepts an open offer and funds second.
• Offer — a signed advert of swap terms (amounts, coins, timelocks, protocol) posted to a board.
• Slip — a private (off-board) offer: the same signed offer envelope encoded as a pactoffer1: string, shared directly.
• Corkboard — a self-hostable order board that stores signed offers and blind-relays sealed blobs.
• Noticeboard — the engine's transport abstraction; a Corkboard or the Nostr aggregate each implement it.
• Nostr / relay — the default transport; offers are Nostr events and a relay is a server that stores and forwards them.
• Merchant — one trading identity = one seed = one data dir; the Bitcoin-Core-wallet analog inside the engine.
• Seed / recovery phrase — the BIP39 mnemonic from which all keys are derived; back it up.
• Passphrase — optional secret that encrypts the seed at rest, entered per session to unlock it.
• Timelock — a deadline (t1/t2) after which a leg's refund path becomes spendable; the taker's is always earlier than the maker's.
• Refund / redeem — redeem claims the counterparty's leg (the trade succeeds); refund reclaims your own leg after the timelock (the trade is unwound).
• Confirmation depth — how many blocks deep an output must be before the engine treats it as final (per-coin, reorg safety).
• RPC — the loopback JSON-RPC 2.0 interface pactd exposes (default port 9737).
• Pair — a tradeable coin combination (e.g. BTCX ↔ BTC), derived from the coins you have configured.
• Base / quote — order-book convention: price is quoted as units of the quote coin per one unit of the base coin.
• BTCX / PoCX — Bitcoin-PoCX; the first supported asset, traded against BTC.
• pactd / Pact / Satchel — pactd is the engine daemon (≈ bitcoind); Pact is the engine project (libswap + pactd + pact-cli); Satchel is the desktop app (≈ bitcoin-qt).