用python实现对称密码算法aes和des的代码

下面是使用Python实现AES和DES的示例代码：

AES加密解密示例代码：

from Crypto.Cipher import AES
import base64

# 加密函数
def aes_encrypt(key, data):
    cipher = AES.new(key.encode('utf-8'), AES.MODE_ECB)
    data = data.encode('utf-8')
    # 补全16位
    length = 16 - (len(data) % 16)
    data += bytes([length]) * length
    ciphertext = cipher.encrypt(data)
    # 转换为base64编码
    return base64.b64encode(ciphertext).decode('utf-8')

# 解密函数
def aes_decrypt(key, ciphertext):
    cipher = AES.new(key.encode('utf-8'), AES.MODE_ECB)
    # 解码base64
    ciphertext = base64.b64decode(ciphertext)
    data = cipher.decrypt(ciphertext)
    # 去除补位
    length = data[-1]
    data = data[:-length]
    return data.decode('utf-8')

# 测试
key = '0123456789abcdef'
data = 'hello world'
ciphertext = aes_encrypt(key, data)
print(ciphertext)
plaintext = aes_decrypt(key, ciphertext)
print(plaintext)

DES加密解密示例代码：

from Crypto.Cipher import DES
import base64

# 加密函数
def des_encrypt(key, data):
    cipher = DES.new(key.encode('utf-8'), DES.MODE_ECB)
    data = data.encode('utf-8')
    # 补全8位
    length = 8 - (len(data) % 8)
    data += bytes([length]) * length
    ciphertext = cipher.encrypt(data)
    # 转换为base64编码
    return base64.b64encode(ciphertext).decode('utf-8')

# 解密函数
def des_decrypt(key, ciphertext):
    cipher = DES.new(key.encode('utf-8'), DES.MODE_ECB)
    # 解码base64
    ciphertext = base64.b64decode(ciphertext)
    data = cipher.decrypt(ciphertext)
    # 去除补位
    length = data[-1]
    data = data[:-length]
    return data.decode('utf-8')

# 测试
key = '01234567'
data = 'hello world'
ciphertext = des_encrypt(key, data)
print(ciphertext)
plaintext = des_decrypt(key, ciphertext)
print(plaintext)

注意：这里仅提供示例代码，实际使用需要根据具体情况进行调整和优化。同时，使用对称密码算法时，需要注意密钥的安全性和保密性。