Understanding Private/Public Keys and Addresses in Ethereum Using Python

The author, a master's graduate in artificial intelligence, introduces blockchain cryptography concepts and demonstrates how to work with Ethereum keys using Python.

1. Relationship between private key, public key, and address – Private and public keys are generated by elliptic curve cryptography; the public key cannot be reverse‑engineered to obtain the private key. The public key is used to verify signatures, while the address is a shortened, hashed representation of the public key obtained via SHA‑256, RIPEMD‑160, and Base58 encoding.

2. Encryption flow – The private key signs a message (producing a signature). The counterpart uses the sender’s public key to verify the signature, ensuring the message has not been tampered with.

3. Python implementation (Ethereum)

Generating keys

<code>from eth_account import Account
from eth_utils.hexadecimal import encode_hex
from eth_account.messages import encode_defunct
import json

def get_key(key):
    """
    获取公钥私钥
    :return: 返回公钥、私钥
    """
    ac1 = Account.create(key)
    return encode_hex(ac1.key), ac1.address
</code>

The generated output includes a private key, public key, and address (shown as example values).

Signing a message

<code>def message_sign(text, prv_key):
    """
    基于私钥获取签名
    :param text: 待签名的文本
    :param prv_key: 私钥
    :return: 签名
    """
    try:
        message = encode_defunct(text=text)
        result = Account.sign_message(message, prv_key)
        result = str(result)
        result = result[result.find("'signature':"):result.find(')})')]
        return result[result.find("(") + 2:].replace("'", '')
    except:
        return '私钥格式不对'
</code>

The function returns a hexadecimal signature string.

Verifying a signature

<code>def verifity(text, signature, address):
    """
    验证签名
    :param text: 原文本
    :param signature: 签名
    :param address: 公钥
    :return: 验证结果
    """
    try:
        message = encode_defunct(text=text)
        address_new = Account.recover_message(message, signature=signature)
        if address == address_new:
            return '验证一致'
        else:
            return '验证失败'
    except:
        return '格式错误'
</code>

The verification function compares the recovered address with the expected address and reports consistency.

Deriving an address from a private key

<code>def recover_address(prv_key):
    """
    基于私钥推出地址
    :param prv_key: 私钥
    :return: 地址
    """
    try:
        acct = Account.from_key(prv_key)
        return acct.address
    except:
        return '格式错误'
</code>

This demonstrates that the private key can be used to compute the corresponding address.

4. Conclusion – The tutorial uses the eth_account Python package, which can be installed via pip install eth_account . The library also supports additional features such as address derivation from transaction hashes and public‑key encryption.