DES python 简单实现
时间: 2023-09-05 07:04:35 浏览: 109
### 回答1:
以下是一个简单的 Python 实现 DES 加密算法的示例代码:
```python
from Crypto.Cipher import DES
# 设置密钥,必须是8字节
key = b'abcdefgh'
# 设置加密模式为 ECB
cipher = DES.new(key, DES.MODE_ECB)
# 需要加密的数据,必须是8字节的整数倍
data = b'12345678'
# 加密
encrypted = cipher.encrypt(data)
print('加密后的数据:', encrypted)
# 解密
decrypted = cipher.decrypt(encrypted)
print('解密后的数据:', decrypted)
```
需要注意的是,使用 DES 算法进行加密时,密钥必须是8字节,而加密数据必须是8字节的整数倍。此外,由于 DES 算法已经被证明不够安全,建议使用更加安全的加密算法,例如 AES 算法。
### 回答2:
DES(Data Encryption Standard)即数据加密标准,是一种对称密钥加密算法。下面是一个使用Python语言简单实现DES的示例。
```python
import pyDes
# 定义密钥
key = b"01234567"
# 定义明文
plaintext = "Hello, world!"
# 创建DES对象
des = pyDes.des(key, pyDes.ECB, b"\0\0\0\0\0\0\0\0", pad=None, padmode=pyDes.PAD_PKCS5)
# 加密明文
ciphertext = des.encrypt(plaintext)
# 将密文转为十六进制格式
hex_ciphertext = ciphertext.hex()
print("明文:", plaintext)
print("密钥:", key.decode())
print("密文:", hex_ciphertext)
```
以上代码使用了第三方库`pyDes`来实现DES加密算法。首先定义了8字节长度的密钥和明文。然后创建了一个DES对象,将密钥和加密模式传递给它。在这个示例中,我们使用了ECB模式,并且没有使用任何补位方式。接下来,使用`encrypt`方法对明文进行加密,并将密文转换为十六进制格式。最后,打印出明文、密钥和密文。
需要注意的是,这只是一个简单的示例,实际使用中应该更加复杂和安全。另外,为了完成解密过程,你还需要使用相同的密钥和加密模式来创建一个DES对象,并使用`decrypt`方法对密文进行解密。
### 回答3:
DES(Data Encryption Standard),即数据加密标准,是一种对称密钥加密算法,广泛应用于保护数据的机密性。下面是一个用Python简单实现DES的例子:
```python
import itertools
from bitarray import bitarray
# 初始化置换表和S盒
IP = [58, 50, 42, 34, 26, 18, 10, 2,
60, 52, 44, 36, 28, 20, 12, 4,
62, 54, 46, 38, 30, 22, 14, 6,
64, 56, 48, 40, 32, 24, 16, 8,
57, 49, 41, 33, 25, 17, 9, 1,
59, 51, 43, 35, 27, 19, 11, 3,
61, 53, 45, 37, 29, 21, 13, 5,
63, 55, 47, 39, 31, 23, 15, 7]
PC1 = [57, 49, 41, 33, 25, 17, 9, 1,
58, 50, 42, 34, 26, 18, 10, 2,
59, 51, 43, 35, 27, 19, 11, 3,
60, 52, 44, 36, 63, 55, 47, 39,
31, 23, 15, 7, 62, 54, 46, 38,
30, 22, 14, 6, 61, 53, 45, 37,
29, 21, 13, 5, 28, 20, 12, 4]
PC2 = [14, 17, 11, 24, 1, 5,
3, 28, 15, 6, 21, 10,
23, 19, 12, 4, 26, 8,
16, 7, 27, 20, 13, 2,
41, 52, 31, 37, 47, 55,
30, 40, 51, 45, 33, 48,
44, 49, 39, 56, 34, 53,
46, 42, 50, 36, 29, 32]
E = [32, 1, 2, 3, 4, 5,
4, 5, 6, 7, 8, 9,
8, 9, 10, 11, 12, 13,
12, 13, 14, 15, 16, 17,
16, 17, 18, 19, 20, 21,
20, 21, 22, 23, 24, 25,
24, 25, 26, 27, 28, 29,
28, 29, 30, 31, 32, 1]
SBOX = [
[
[14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7],
[0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8],
[4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0],
[15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13]
],
#
# 省略其余表格
#
]
P = [16, 7, 20, 21, 29, 12, 28, 17,
1, 15, 23, 26, 5, 18, 31, 10,
2, 8, 24, 14, 32, 27, 3, 9,
19, 13, 30, 6, 22, 11, 4, 25]
# 左循环移位
def left_rotate(bits, n):
return bits[n:] + bits[:n]
# 生成子密钥
def generate_sub_keys(key):
key = permutation(key, PC1)
sub_keys = []
for i in range(16):
key = left_rotate(key[:28], SHIFTS[i]) + left_rotate(key[28:], SHIFTS[i])
sub_key = permutation(key, PC2)
sub_keys.append(sub_key)
return sub_keys
# 执行初始置换和逆置换
def process_message(message, keys):
message = permutation(message, IP)
left, right = message[:32], message[32:]
for i in range(16):
new_left = right
new_right = xor(left, feistel(right, keys[i]))
left, right = new_left, new_right
message = permutation(right + left, IP_INV)
return message
# 轮函数
def feistel(right, key):
expanded = permutation(right, E)
xored = xor(expanded, key)
output = []
for i in range(8):
bits = xored[i*6:(i+1)*6]
row = int(bits[0] + bits[5], 2)
col = int(''.join(bits[1:5]), 2)
val = SBOX[i][row][col]
output.append('{0:04b}'.format(val))
return permutation(''.join(output), P)
# 异或操作
def xor(a,b):
return ''.join(str(int(x) ^ int(y)) for x,y in zip(a,b))
# 执行置换操作
def permutation(bits, table):
return ''.join(bits[x-1] for x in table)
# 示例用法
if __name__ == "__main__":
# 输入明文和密钥
plain_text = "0000000100100011010001010110011110001001101010111100110111101111"
key = "0001001100110100010101110111100110011011101111001101111111110001"
# 生成子密钥
sub_keys = generate_sub_keys(key)
# 加密并打印结果
encrypted = process_message(plain_text, sub_keys)
print("Encrypted: ", encrypted)
# 解密并打印结果
decrypted = process_message(encrypted, sub_keys[::-1])
print("Decrypted: ", decrypted)
```
以上是一个使用Python简单实现的DES加解密算法的例子。通过将明文和密钥作为输入,生成子密钥并执行加密和解密过程,最终输出加密后的密文和解密后的明文。请注意,此实现仅用于教学或参考目的,实际应用中应使用更安全和高效的加密算法。
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