23 lines
762 B
Text
23 lines
762 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 if condition then right else left fi, if condition then left else right fi
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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] digest = leaf
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// Loop up the tree
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for u32 i in 0..DEPTH do
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u32[8] left, u32[8] right = select(directionSelector[i], digest, path[i])
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digest = hash(left, right)
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endfor
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return digest == root
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