Build merkle tree

Build a Keccak-256 Merkle root and inclusion proof from ordered text leaves.

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ToolMerkle Tree Builder
Input
Output
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Preview

How it works

Each UTF-8 leaf is Keccak-256-hashed, adjacent hashes are concatenated left-to-right, and an odd final node is paired with itself. The selected leaf records each sibling hash and side while the final level supplies the root.

  • The first value is selected when no proof index is supplied.
  • Duplicating an odd node keeps every level pairable without a sentinel hash.

Worked example

Four values, proof for the second
A balanced tree, so no duplication is needed
Input
											Values: ["alice","bob","carol","dave"]
Leaf index: 1
Output
												Merkle root hex: 415e49eafecf2263e29c49dcf6473e52dbf4b0f03090ff949b52aabc88aa1e8b
Leaf hash hex: 38e47a7b719dce63662aeaf43440326f551b8a7ee198cee35cb5d517f2d296a2
Tree depth: 2
Leaf count: 4
Proof sibling hashes: 9c0257114eb9399a2985f8e75dad7600c5d89fe3824ffa99ec1c3eb8bf3b0501, b81613f04cd9ce07b4781be9bbaa86a503220985be2a3f168b30d158da0db0e2
Proof sibling positions: left, right

When to use this

Airdrop contracts verify user proofs, rollups publish state roots, and content manifests commit many records to one digest.

Edge cases

  • An odd number of leaves duplicates the last hash at that level; dropping it changes the root.
  • The visible text é is UTF-8 encoded, so a legacy single-byte client will produce another leaf.
  • Reordering the same values changes parent hashes even though the set is unchanged.

References