使用python实现简单的序列密码

#!/usrs/bin/env python
print '\nStream Ciphers:\n'
before = 'One apple a day, keeps the doctor away!'
after = ""
i = 1
for each in before:
after += chr(ord(each)^(63+i))
if i == 4:
i = 1
print 'before: ',before,'\n'
print 'after: ',after,'\n'
revert = ""
i = 1
for each in after:
revert += chr(ord(each)^(63+i))
if i == 4:
i = 1
print 'revert: ',revert,'\n'