How to Salt Passwords per User in Python

import hashlib
import secrets

def hash_password(password: str, salt: str | None = None) -> tuple[str, str]:
    """Hash a password with a random salt (or provided salt).

    Returns:
        (salt_hex, password_hash_hex)
    """
    if salt is None:
        salt = secrets.token_hex(16)
    salted = (salt + password).encode("utf-8")
    digest = hashlib.sha256(salted).hexdigest()
    return salt, digest

def verify_password(password: str, salt: str, expected_hash: str) -> bool:
    """Check if password matches the stored salt + hash."""
    _, computed_hash = hash_password(password, salt)
    return secrets.compare_digest(computed_hash, expected_hash)

if __name__ == "__main__":
    users = {
        "alice": None,
        "bob": None,
    }

    for username in users:
        users[username] = hash_password("correct horse battery staple")

    print("Stored hashes (salt, hash):")
    for username, (salt, pw_hash) in users.items():
        print(f"{username}: salt={salt[:8]}... hash={pw_hash[:12]}...")

    print("\nVerification:")
    print("alice correct:", verify_password("correct horse battery staple", *users["alice"]))
    print("alice wrong:", verify_password("wrong", *users["alice"]))