Ethereum: What is the approach to calculate an Ethereum address from a 256 bit private key?

Calculating Ethereum Addresses from Private Keys: A Step-by-Step Guide

Ethereum is a decentralized, open-source blockchain platform that enables smart contract development and decentralized applications (dApps). One of the key aspects of interacting with Ethereum is generating and managing private keys. However, some users may need to convert their existing private keys into Ethereum addresses, which can be challenging without the correct tools.

In this article, we will explore how to calculate Ethereum addresses from 256-bit private keys using a wrapper around Keccak-256 hash function.

Keccak-256 Hash Function

The Keccak-256 hash function is a cryptographic algorithm that produces a fixed-size, 256-bit (32-byte) hash value for input data. In the context of Ethereum, this hash value will be used to generate an Ethereum address.

Here’s an example implementation of the Keccak-256 hash function in Python:


import hashlib


def keccak_256(private_key):

    """Returns a 256-bit (32-byte) hash value for the given private key."""

    return hashlib.sha3_256(private_key).digest()

Calculating Ethereum Addresses from Private Keys

To calculate an Ethereum address from a 256-bit private key, we need to convert the private key to a hexadecimal string. Then, we can use the Keccak-256 hash function to generate the Ethereum address.

Here’s a step-by-step guide:

Convert the 256-bit private key to a hexadecimal string:


private_key = "0x0123456789abcdef"

hex_private_key = private_key.hex()

Calculate the Ethereum address using Keccak-256 hash function:


keccak_hash_value = keccak_256(hex_private_key)

ethereum_address = int.from_bytes(keccak_hash_value, byteorder='big')

In this example:

private_key is a string representing the 256-bit private key.

hex_private_key is the hexadecimal representation of the private key obtained in step 1.

keccak_hash_value is the resulting hash value from the Keccak-256 function.

ethereum_address is an integer representing the Ethereum address, where each byte represents a block number and each word represents a transaction ID.

Wrapper Around Keccak

The above implementation can be wrapped around into a reusable library or tool. Here’s an example using Python:


def calculate_ethereum_address(private_key):

    """Returns an Ethereum address for the given private key."""

    def keccak_hash(key):

        return hashlib.sha3_256(key).digest()


    hex_private_key = private_key.hex()

    keccak_hash_value = keccak_hash(hex_private_key)

    ethereum_address = int.from_bytes(keccak_hash_value, byteorder='big')


    return ethereum_address

This wrapper provides a simple and easy-to-use API for calculating Ethereum addresses from private keys.

Conclusion

In this article, we have explored how to calculate Ethereum addresses from 256-bit private keys using the Keccak-256 hash function. By following the steps outlined above, you can generate Ethereum addresses from your existing private keys. This approach provides a convenient and efficient way to manage private keys on Ethereum and perform smart contract development.

Note: Keep in mind that this is just an example implementation, and you should always handle private keys securely in real-world applications.

Ethereum Block Hashing