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zeekay
9c9106017e
The single place a Lux cross-chain atomic swap is constructed across all three legs, composed from one shared primitive: - secret.go — Secret [32]byte, Hashlock() = sha256(secret), constant-time VerifyPreimage. THE source of the SHA-256 hashlock every leg shares (one 32-byte preimage unlocks BTC, the LP-90A0 swap precompile, and the EVM LXSwapHTLC.sol); keccak is explicitly excluded. - bitcoin.go — the fixed P2WSH HTLC script (OP_IF SHA256/EQUALVERIFY/CHECKSIG // OP_ELSE CLTV/DROP/CHECKSIG), P2WSHAddress, and claim/refund witnesses signed with real BIP143 segwit-v0 sighash via btcd txscript (no hand-rolled sighash; low-S RFC6979 sigs). - evm.go — lock/claim/refund calldata; selectors DERIVED from the canonical ABI signatures and asserted equal to the precompile's 0x4da2c728 / 0x84cc9dfb / 0x7249fbb6. Tests (-race) include real txscript.Engine execution proofs: claim spends with the correct preimage and fails with a wrong one; refund spends at/after locktime and fails before / with CLTV disabled. btcd pinned v0.24.2 (v0.26.0 split chaincfg/wire/txscript into /v2 modules and breaks the build).
81 lines
2.3 KiB
Go
81 lines
2.3 KiB
Go
// Copyright (C) 2019-2025, Lux Industries Inc. All rights reserved.
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// See the file LICENSE for licensing terms.
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package htlc
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import (
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"encoding/binary"
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"math/big"
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"github.com/luxfi/crypto"
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"github.com/luxfi/geth/common"
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)
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// EVM-leg ABI signatures. These canonical strings are the SINGLE source of truth
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// for the selectors below; the documented hex (asserted in the tests) is derived
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// from them, never hand-entered, so it cannot drift from swap.go / LXSwapHTLC.sol.
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const (
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lockSig = "lock(bytes32,address,address,address,uint256,uint64)"
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claimSig = "claim(bytes32,bytes32)"
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refundSig = "refund(bytes32)"
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)
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// 4-byte selectors: keccak256(signature)[:4]. lock=0x4da2c728, claim=0x84cc9dfb,
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// refund=0x7249fbb6.
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var (
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selLock = selector(lockSig)
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selClaim = selector(claimSig)
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selRefund = selector(refundSig)
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)
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func selector(sig string) [4]byte {
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var s [4]byte
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copy(s[:], crypto.Keccak256([]byte(sig)))
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return s
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}
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// LockCalldata encodes lock(hashlock, recipient, refund, asset, amount, timeout)
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// for the swap precompile / LXSwapHTLC.sol. hashlock is the SAME h = SHA256(s)
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// the Bitcoin leg locks under, so one preimage settles both.
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func LockCalldata(hashlock [32]byte, recipient, refund, asset common.Address, amount *big.Int, timeout uint64) []byte {
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out := make([]byte, 0, 4+6*32)
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out = append(out, selLock[:]...)
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out = append(out, hashlock[:]...)
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out = append(out, word(recipient.Bytes())...)
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out = append(out, word(refund.Bytes())...)
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out = append(out, word(asset.Bytes())...)
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out = append(out, word(amount.Bytes())...)
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out = append(out, word(u64(timeout))...)
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return out
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}
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// ClaimCalldata encodes claim(swapId, preimage). preimage is the 32-byte secret s.
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func ClaimCalldata(swapID [32]byte, preimage Secret) []byte {
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out := make([]byte, 0, 4+2*32)
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out = append(out, selClaim[:]...)
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out = append(out, swapID[:]...)
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out = append(out, preimage[:]...)
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return out
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}
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// RefundCalldata encodes refund(swapId).
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func RefundCalldata(swapID [32]byte) []byte {
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out := make([]byte, 0, 4+32)
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out = append(out, selRefund[:]...)
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out = append(out, swapID[:]...)
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return out
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}
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// word left-pads a big-endian byte string to a 32-byte ABI slot.
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func word(b []byte) []byte {
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w := make([]byte, 32)
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copy(w[32-len(b):], b)
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return w
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}
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func u64(v uint64) []byte {
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var b [8]byte
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binary.BigEndian.PutUint64(b[:], v)
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return b[:]
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}
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