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author | Russell O'Connor <roconnor@blockstream.io> | 2022-08-19 11:59:18 -0400 |
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committer | Russell O'Connor <roconnor@blockstream.io> | 2022-11-21 12:38:53 -0500 |
commit | dee89438b82e94474ebaa31367035f98b4636dac (patch) | |
tree | 4c4f663303788784b299f476accc0a8b9f0a2475 /src | |
parent | 8e3fc9942729716e95907008fcf36eee758c3a6a (diff) | |
download | bitcoin-dee89438b82e94474ebaa31367035f98b4636dac.tar.xz |
Abstract out ComputeTapbranchHash
Diffstat (limited to 'src')
-rw-r--r-- | src/script/interpreter.cpp | 19 | ||||
-rw-r--r-- | src/script/interpreter.h | 3 | ||||
-rw-r--r-- | src/script/standard.cpp | 9 | ||||
-rw-r--r-- | src/test/script_tests.cpp | 7 |
4 files changed, 24 insertions, 14 deletions
diff --git a/src/script/interpreter.cpp b/src/script/interpreter.cpp index 5148265b9c..c06d0370c9 100644 --- a/src/script/interpreter.cpp +++ b/src/script/interpreter.cpp @@ -1830,6 +1830,17 @@ uint256 ComputeTapleafHash(uint8_t leaf_version, Span<const unsigned char> scrip return (HashWriter{HASHER_TAPLEAF} << leaf_version << CompactSizeWriter(script.size()) << script).GetSHA256(); } +uint256 ComputeTapbranchHash(Span<const unsigned char> a, Span<const unsigned char> b) +{ + HashWriter ss_branch{HASHER_TAPBRANCH}; + if (std::lexicographical_compare(a.begin(), a.end(), b.begin(), b.end())) { + ss_branch << a << b; + } else { + ss_branch << b << a; + } + return ss_branch.GetSHA256(); +} + uint256 ComputeTaprootMerkleRoot(Span<const unsigned char> control, const uint256& tapleaf_hash) { assert(control.size() >= TAPROOT_CONTROL_BASE_SIZE); @@ -1839,14 +1850,8 @@ uint256 ComputeTaprootMerkleRoot(Span<const unsigned char> control, const uint25 const int path_len = (control.size() - TAPROOT_CONTROL_BASE_SIZE) / TAPROOT_CONTROL_NODE_SIZE; uint256 k = tapleaf_hash; for (int i = 0; i < path_len; ++i) { - HashWriter ss_branch{HASHER_TAPBRANCH}; Span node{Span{control}.subspan(TAPROOT_CONTROL_BASE_SIZE + TAPROOT_CONTROL_NODE_SIZE * i, TAPROOT_CONTROL_NODE_SIZE)}; - if (std::lexicographical_compare(k.begin(), k.end(), node.begin(), node.end())) { - ss_branch << k << node; - } else { - ss_branch << node << k; - } - k = ss_branch.GetSHA256(); + k = ComputeTapbranchHash(k, node); } return k; } diff --git a/src/script/interpreter.h b/src/script/interpreter.h index 5530d824f2..790098f9df 100644 --- a/src/script/interpreter.h +++ b/src/script/interpreter.h @@ -334,6 +334,9 @@ public: /** Compute the BIP341 tapleaf hash from leaf version & script. */ uint256 ComputeTapleafHash(uint8_t leaf_version, Span<const unsigned char> script); +/** Compute the BIP341 tapbranch hash from two branches. + * Spans must be 32 bytes each. */ +uint256 ComputeTapbranchHash(Span<const unsigned char> a, Span<const unsigned char> b); /** Compute the BIP341 taproot script tree Merkle root from control block and leaf hash. * Requires control block to have valid length (33 + k*32, with k in {0,1,..,128}). */ uint256 ComputeTaprootMerkleRoot(Span<const unsigned char> control, const uint256& tapleaf_hash); diff --git a/src/script/standard.cpp b/src/script/standard.cpp index b5ba542ce0..2b7c120eaf 100644 --- a/src/script/standard.cpp +++ b/src/script/standard.cpp @@ -370,12 +370,7 @@ bool IsValidDestination(const CTxDestination& dest) { leaf.merkle_branch.push_back(a.hash); ret.leaves.emplace_back(std::move(leaf)); } - /* Lexicographically sort a and b's hash, and compute parent hash. */ - if (a.hash < b.hash) { - ret.hash = (HashWriter{HASHER_TAPBRANCH} << a.hash << b.hash).GetSHA256(); - } else { - ret.hash = (HashWriter{HASHER_TAPBRANCH} << b.hash << a.hash).GetSHA256(); - } + ret.hash = ComputeTapbranchHash(a.hash, b.hash); return ret; } @@ -607,7 +602,7 @@ std::optional<std::vector<std::tuple<int, std::vector<unsigned char>, int>>> Inf node.done = true; stack.pop_back(); } else if (node.sub[0]->done && !node.sub[1]->done && !node.sub[1]->explored && !node.sub[1]->hash.IsNull() && - (HashWriter{HASHER_TAPBRANCH} << node.sub[1]->hash << node.sub[1]->hash).GetSHA256() == node.hash) { + ComputeTapbranchHash(node.sub[1]->hash, node.sub[1]->hash) == node.hash) { // Whenever there are nodes with two identical subtrees under it, we run into a problem: // the control blocks for the leaves underneath those will be identical as well, and thus // they will all be matched to the same path in the tree. The result is that at the location diff --git a/src/test/script_tests.cpp b/src/test/script_tests.cpp index 935194057c..e74678394f 100644 --- a/src/test/script_tests.cpp +++ b/src/test/script_tests.cpp @@ -1817,7 +1817,14 @@ BOOST_AUTO_TEST_CASE(bip341_keypath_test_vectors) } } +} +BOOST_AUTO_TEST_CASE(compute_tapbranch) +{ + uint256 hash1 = uint256S("8ad69ec7cf41c2a4001fd1f738bf1e505ce2277acdcaa63fe4765192497f47a7"); + uint256 hash2 = uint256S("f224a923cd0021ab202ab139cc56802ddb92dcfc172b9212261a539df79a112a"); + uint256 result = uint256S("a64c5b7b943315f9b805d7a7296bedfcfd08919270a1f7a1466e98f8693d8cd9"); + BOOST_CHECK_EQUAL(ComputeTapbranchHash(hash1, hash2), result); } BOOST_AUTO_TEST_SUITE_END() |