python实现维尼吉亚密码

#key='relations'

#plaintext='tomorrowiwillhaveagood'

key='helloworld'

plaintext=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=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)