python编写加密程序_python编写的维吉尼亚密码加解密程序

维吉尼亚密码表

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#维吉尼亚密码 加密

key=‘helloworld‘

plaintext=‘whereisthekey‘

#key=‘relations‘

#plaintext=‘tobeornottobeth‘

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

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#维吉尼亚加密算法 解密

key=‘helloworld‘

ciphertext=‘dlpcsegkshrij‘

#key=‘relations‘

#ciphertext=‘ksmehzbblk‘

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

原文：http://whbill./3280780/1726430