python实现sm4加解密

Python可以使用`cryptography`库来实现SM4加解密算法。以下是一个简单的示例代码：

from cryptography.hazmat.primitives import padding
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes

def sm4_encrypt(key, plaintext):
    # 对明文进行填充
    padder = padding.PKCS7(128).padder()
    padded_data = padder.update(plaintext) + padder.finalize()

    # 生成随机IV
    iv = os.urandom(16)

    # 创建SM4加密器对象
    cipher = Cipher(algorithms.SM4(key), modes.CBC(iv))

    # 加密明文
    encryptor = cipher.encryptor()
    ciphertext = encryptor.update(padded_data) + encryptor.finalize()

    return iv + ciphertext

def sm4_decrypt(key, ciphertext):
    # 提取IV
    iv = ciphertext[:16]
    ciphertext = ciphertext[16:]

    # 创建SM4解密器对象
    cipher = Cipher(algorithms.SM4(key), modes.CBC(iv))

    # 解密密文
    decryptor = cipher.decryptor()
    padded_data = decryptor.update(ciphertext) + decryptor.finalize()

    # 去除填充
    unpadder = padding.PKCS7(128).unpadder()
    plaintext = unpadder.update(padded_data) + unpadder.finalize()

    return plaintext

# 使用示例
key = b'\x01\x23\x45\x67\x89\xab\xcd\xef\xfe\xdc\xba\x98\x76\x54\x32\x10'
plaintext = b'Hello, World!'
ciphertext = sm4_encrypt(key, plaintext)
decrypted_plaintext = sm4_decrypt(key, ciphertext)

print("加密后的结果：", ciphertext)
print("解密后的结果：", decrypted_plaintext)