如何在python中使用加密的RSA私钥(AES-256-CBC)签名数据

from cryptography.hazmat.primitives import serialization, hashes
from cryptography.hazmat.primitives.asymmetric import padding
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC

# 1. 加载RSA私钥
with open('private_key.pem', 'rb') as key_file:
    private_key = serialization.load_pem_private_key(
        key_file.read(),
        password=None
    )

# 2. 生成随机密钥和初始化向量
salt = b'salt'  # 随机盐值
password = b'password'  # 自定义密码
kdf = PBKDF2HMAC(
    algorithm=hashes.SHA256(),
    length=16,
    salt=salt,
    iterations=100000,
)
key = kdf.derive(password)
iv = b'initialization_vector'  # 随机初始化向量

# 3. 加密数据
cipher = Cipher(algorithms.AES(key), modes.CBC(iv))
encryptor = cipher.encryptor()
ciphertext = encryptor.update(data) + encryptor.finalize()

# 4. RSA私钥签名
signature = private_key.sign(
    key + iv,
    padding.PSS(
        mgf=padding.MGF1(hashes.SHA256()),
        salt_length=padding.PSS.MAX_LENGTH
    ),
    hashes.SHA256()
)