26 lines
752 B
Text
26 lines
752 B
Text
import "hashes/sha256/512bit" as hash;
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import "hashes/utils/256bitsDirectionHelper" as multiplex;
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const u32 DEPTH = 3;
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def select(bool condition, u32[8] left, u32[8] right) -> (u32[8], u32[8]) {
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return (condition ? right : left, condition ? left : right);
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}
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// Merke-Tree inclusion proof for tree depth 4 using sha256
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// directionSelector => true if current digest is on the rhs of the hash
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def main(u32[8] root, private u32[8] leaf, private bool[DEPTH] directionSelector, private u32[DEPTH][8] path) -> bool {
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// Start from the leaf
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u32[8] mut digest = leaf;
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// Loop up the tree
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for u32 i in 0..DEPTH {
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(u32[8], u32[8]) s = select(directionSelector[i], digest, path[i]);
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digest = hash(s.0, s.1);
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}
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return digest == root;
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}
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