Python实现的维尼吉亚密码算法示例

# -*- coding:utf-8 -*-
#key='relations'
#plaintext='tomorrowiwillhaveagood'
print("测试结果：")
key='helloworld'
plaintext=raw_input('请输入明文：')
ascii='abcdefghijklmnopqrstuvwxyz'
keylen=len(key)
ptlen=len(plaintext)
ciphertext =''
i =0
while i < ptlen:
 j = i % keylen
 k = ascii.index(key[j])
 m = ascii.index(plaintext[i])
 ciphertext += ascii[(m+k)%26]
 i +=1
print(ciphertext)
#维吉尼亚加密算法 解密
key='helloworld'
ciphertext=raw_input('请输入密文：')
ascii='abcdefghijklmnopqrstuvwxyz'
keylen=len(key)
ctlen=len(ciphertext)
plaintext =''
i =0
while i < ctlen:
 j = i % keylen
 k = ascii.index(key[j])
 m = ascii.index(ciphertext[i])
 if m < k:
  m +=26
 plaintext += ascii[m-k]
 i +=1
print(plaintext)