Generate Merkle Root

How to verify the lottery/raffle outcome.

Generating Merkle Root for verification

Step 1: Construct Leaf Bytes

For each holder:

1. Encode the public key as 32 bytes

2. Convert the start, end, and leaf index values into 8-byte little-endian integers.

3. Concatenate the values in this order:

​leaf_bytes = pubkey_bytes || start_bytes || end_bytes || leaf_index_bytes

This ensures the leaf structure matches the on-chain verification logic.

Step 2: Hash Leaves (Double Hashing)

• Apply Keccak256 to the leaf bytes.

• Then, hash the result again (double hashing):

​leaf_hash = Keccak256(Keccak256(leaf_bytes))

Step 3: Build the Merkle Tree

1. Start with all the double-hashed leaves.

2. Iteratively build parent nodes:

3. Pair adjacent hashes (left, right) and compute the parent hash:

parent_hash = Keccak256(left || right)

• If there is an odd number of nodes at the current level, duplicate the last node:

parent_hash = Keccak256(last_node || last_node)3. Replace the current level with the newly computed parent hashes. 4. Repeat until only one hash remains.

Step 4: Merkle Root

• The final single hash at the top of the tree is the Merkle root.

• This root is used in the smart contract to verify individual proofs against the tree.

Important Notes:

• Leaf ordering: The order of leaves determines the root; it must be consistent with proof generation.

• Intermediate nodes: Only single Keccak256 hash is applied per parent node.

• Odd leaves: The last node is duplicated if the number of nodes at a level is odd.

• Double hash: Only applies to leaves, not to parent nodes.

• Hashing algorithm: Use Keccak256 consistently across leaves and nodes.