python实现简单加密解密机制

# -*- coding: utf-8 -*-
import os,sys 
reload(sys) 
sys.setdefaultencoding('utf8') 
import string
 
def suanfa(key):
  alp = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
  jiami_key = {}
  jiemi_key = {}
 
  list0 = list(alp)
  list1 = list(key)
  list2 = list(alp)
  for n in list1:
    for m in list2:
      if m == n:
        list2.remove(m)
 
  alp1 = ''.join(list2)
  key1 = key + alp1
  list3 = list(key1)
 
  a = 0
  if a < len(list0):
    for m in list0:
      jiami_key[m] = list3[a]
      a = a + 1
  
  b = 0
  if b < len(list3):
    for n in list3:
      jiemi_key[n] = list0[b]
      b = b + 1
  
  #print jiami_key
  #print jiemi_key
  return jiami_key, jiemi_key 
 
def bianma(key_dic, data):
  list_data = list(data)
  data1 = []
  for a in list_data:
     if a == ' ':
       data1.append(a)
 
     elif a.islower():
       a = a.upper()
       if key_dic.has_key(a):
         x = key_dic[a]
         data1.append(x.lower())
 
     elif a.isupper():
       if key_dic.has_key(a):
         x = key_dic[a]
         data1.append(x)
     else:
       data1.append(a)
 
  data2 = ''.join(data1)
  #print data2
  return data2
 
def main():
  key = 'ZDFKJMNX'
  data = 'a bdcd sFDGDSGFDG113243 3'
  print "秘钥：" + key
  print "明文：" + data
 
  jiami_key, jiemi_key = suanfa(key)
  miwen = bianma(jiami_key, data)
  mingwen = bianma(jiemi_key, miwen)
 
  print "加密明文所得的密文：" + miwen
  print "解密密文所得的明文：" + mingwen
  return True
 
if __name__ == "__main__":
  main()