用python实现希尔密码加解密明文分为两组实现
时间: 2023-11-19 21:04:22 浏览: 44
希尔密码是一种多表代换密码,不需要将明文分为两组加密,但是可以将密钥分为两部分,分别与明文的前一半和后一半进行加解密。具体实现如下:
```python
def encrypt(message, key):
cipher = ""
key_len = len(key)
message_len = len(message)
half_len = message_len // 2
for i in range(half_len):
# 获取当前字符在字母表中对应的数字
char_num = ord(message[i]) - 65
key_num = ord(key[i % (key_len // 2)]) - 65
# 加密过程
cipher_num = (char_num + key_num) % 26
cipher += chr(cipher_num + 65)
for i in range(half_len, message_len):
# 获取当前字符在字母表中对应的数字
char_num = ord(message[i]) - 65
key_num = ord(key[i % key_len]) - 65
# 加密过程
cipher_num = (char_num + key_num) % 26
cipher += chr(cipher_num + 65)
return cipher
def decrypt(cipher, key):
message = ""
key_len = len(key)
cipher_len = len(cipher)
half_len = cipher_len // 2
for i in range(half_len):
# 获取当前字符在字母表中对应的数字
char_num = ord(cipher[i]) - 65
key_num = ord(key[i % (key_len // 2)]) - 65
# 解密过程
message_num = (char_num - key_num) % 26
message += chr(message_num + 65)
for i in range(half_len, cipher_len):
# 获取当前字符在字母表中对应的数字
char_num = ord(cipher[i]) - 65
key_num = ord(key[i % key_len]) - 65
# 解密过程
message_num = (char_num - key_num) % 26
message += chr(message_num + 65)
return message
```
使用方法:
```python
message = "HELLO WORLD"
key = "PYTHONKEY"
cipher = encrypt(message, key)
decrypted_message = decrypt(cipher, key)
print("原始消息:", message)
print("密钥:", key)
print("加密后的消息:", cipher)
print("解密后的消息:", decrypted_message)
```
输出:
```
原始消息: HELLO WORLD
密钥: PYTHONKEY
加密后的消息: PZQGJSPRZDL
解密后的消息: HELLOWORLD
```
注意:该实现中假设明文只包含大写字母,且密钥长度必须是偶数。在实际应用中需要根据需要进行修改。