Merkle Tree Implementation in JS with keccak256

Question

I coded some Merkle Tree implementations in JavaScript with keccak256. This code takes JSON Objects from the local JSON File that called output.json. It has this type of objects:

{
        "key": "{\"address\":\"0xCA1b1d94C8aDbeD62dB06af2933820098d397D12\",\"type\":\"index\"}",
        "value": "{\"index\":0}"
}

And my code creates the merkle tree from these key-value pairs, selects one of them randomly, finds its index on the tree, hashes it, and tries to concatenate and hash it with its sibling. However, no matter how hard I try to concatenate and hash the same hashes, I never get the same hashes.

Here is the my JS code:


const fs = require('fs');
const keccak256 = require('keccak256');

const json = JSON.parse(fs.readFileSync('output.json', { encoding: 'utf8' }));
let indexArray = [];

function main() {

    const tree = json.map((item) => {
        return {
            key: item.key.toString(),
            value: item.value.toString(),
        };
    });

    searchObject = tree[Math.floor(Math.random() * tree.length)]
    let current = JSON.stringify(searchObject);

    let iter = 0;

    //creating leafs
    for (let i = 0; i < tree.length; i++) {
        let element = tree[i];
        tree[i] = keccak256(JSON.stringify(element));
        indexArray.push(tree[i]);
    }
    
    
    //logging
    for (let i = 0; i < tree.length; i++) {
        //tree[i] = tree[i].toString('hex');
        console.log(`${iter}. layer'ın ${i}. elemanı: ${tree[i].toString('hex')}`);
    }
    iter++;
    
    
    while (tree.length > 1) {
        //create merkle tree
        for (let i = 0; i < tree.length - 1; i++) {
            
            process.stdout.write(`${tree[i].toString('hex')} and ${tree[i+1].toString('hex')}  concatenated and hashed, and the result is this output:`);
            tree[i] = keccak256(tree[i] + tree[i+1]);
            process.stdout.write(`${tree[i].toString('hex')}\n`);
            tree.splice(i+1, 1);
            
        }
        
        //logging
        for (let i = 0; i < tree.length; i++) {
            
            indexArray.push(tree[i]);
            console.log(`${iter}. layer'ın ${i}. elemanı: ${tree[i].toString('hex')}`);
        }
        
        iter++;
    }
    

    console.log(`Merkle root is: ${tree[0].toString('hex')}\n`);

    
   
    indexArray.reverse();
    for (let i = 0; i < indexArray.length; i++) {
        console.log(`${ i }. eleman: ${indexArray[i].toString('hex')}`);
    }


    
    console.log(`\n\nBeginning search...`);
    let dex = null;
    for (let i = 0; i < indexArray.length; i++) {
        if ( keccak256(current).toString('hex') === indexArray[i].toString('hex')) {
            console.log(`\n${searchObject.key + searchObject.value} and its hash ${keccak256(current).toString('hex')} is found at ${i}. index`);
            dex = i;
            break;
        }
    }

   
    
    let hash = null;
    if (dex % 2 == 0) {
        hash = keccak256(  indexArray[dex-1] + current );
        console.log(`\n`);
        console.log(`${keccak256(current).toString('hex')} and its sibling is at ${dex-1} index which is ${indexArray[dex-1].toString('hex')} hashed together and the result is ${hash.toString('hex')}`);
        dex = Math.floor((dex-1)/2);
    }
    else {
        hash = keccak256( current +  indexArray[dex+1]  );
        console.log(`\n`);
        console.log(`${keccak256(current).toString('hex')} and its sibling is at ${dex+1} index which is ${indexArray[dex+1].toString('hex')} hashed together and the result is ${hash.toString('hex')}`);
        dex =  Math.floor((dex-1)/2);
    }

    if (hash === indexArray[dex]) {
        
        console.log(`\nProof is valid!`);
    } else {
       
        console.log(`\nProof is not valid!`);
    }


}

main();

Merkle Tree Implementation in JS with keccak256

0 Answers0