I am trying to recreate the namehash algorithm from EIP-137.

After spending a lot of time trying to create my own algorithm, I tried to find a working python3 package online and couldn't find any.

I have been using the Python web3 api https://web3py.readthedocs.io/en/stable/web3.main.html

Right now, I can successfully get label hashes of names like 'vitalik' and 'eth' with the code below.

from web3 import Web3
w3 = Web3(Web3.HTTPProvider("my_provider"))


However, my implementation is failing when I get to the part where it says "Then, starting with the last component, the previous output is concatenated with the label hash and hashed again."

I have tried almost every way I can think of to do this concatenation. A few of the ways I have tried:

w3.keccak(hexstr=namehash(remainder) + w3.keccak(text=label))
w3.solidityKeccak(['address'], ["vitalik.eth"]).hex()
w3.solidityKeccak(['address', 'address'], ["vitalik", "eth"]).hex()

Nothing seems to give me the correct namehash.

Any help would be appreciated.

1 Answer 1


The following works for me. First I concatenate uint256(0) with keccak(eth) to make the .eth node. Then I concatenate this result with keccak(vitalik) to make vitalik.eth.

x0 = 0
x1 = w3.keccak(text='eth')
eth = w3.solidityKeccak(['uint256', 'bytes32'], [x0, x1])  # this is .eth

vitalik = w3.keccak(text='vitalik')

vitaliketh = w3.solidityKeccak(['bytes32', 'bytes32'], [eth, vitalik])  # this is vitalik.eth
  • 1
    Thank you for this! This code actually didn't work for me at first. I finally realized that my web3 environment was broken. If this happens to anyone else, I used a clean python virtual environment, following the steps here: web3py.readthedocs.io/en/stable/… After this, your code worked perfect. Commented Sep 14, 2022 at 17:19

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