python實現DES加密解密方法執行個體詳解

本文執行個體講述了python實現DES加密解密方法。分享給大家供大家參考。具體分析如下：

實現功能：加密中文等字串
密鑰與明文可以不等長
這裡只貼代碼，加密過程可以自己百度，此處python代碼沒有最佳化

1. desstruct.py DES加密中要使用的結構體

ip= (58, 50, 42, 34, 26, 18, 10, 2,   60, 52, 44, 36, 28, 20, 12, 4,   62, 54, 46, 38, 30, 22, 14, 6,   64, 56, 48, 40, 32, 24, 16, 8,   57, 49, 41, 33, 25, 17, 9 , 1,   59, 51, 43, 35, 27, 19, 11, 3,   61, 53, 45, 37, 29, 21, 13, 5,   63, 55, 47, 39, 31, 23, 15, 7)ip_1=(40, 8, 48, 16, 56, 24, 64, 32,   39, 7, 47, 15, 55, 23, 63, 31,   38, 6, 46, 14, 54, 22, 62, 30,   37, 5, 45, 13, 53, 21, 61, 29,   36, 4, 44, 12, 52, 20, 60, 28,   35, 3, 43, 11, 51, 19, 59, 27,   34, 2, 42, 10, 50, 18, 58, 26,   33, 1, 41, 9, 49, 17, 57, 25)e =(32, 1, 2, 3, 4, 5, 4, 5,     6, 7, 8, 9, 8, 9, 10, 11,    12,13, 12, 13, 14, 15, 16, 17,   16,17, 18, 19, 20, 21, 20, 21,   22, 23, 24, 25,24, 25, 26, 27,   28, 29,28, 29, 30, 31, 32, 1)p=(16, 7, 20, 21, 29, 12, 28, 17,   1, 15, 23, 26, 5, 18, 31, 10,    2, 8, 24, 14, 32, 27, 3, 9,   19, 13, 30, 6, 22, 11, 4, 25)s=[ [[14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7],   [0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8],   [4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0],   [15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13]],   [[15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10],   [3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5],   [0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15],   [13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9]],   [[10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8],   [13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1],   [13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7],   [1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12]],  [[7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15],   [13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14,9],   [10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4],   [3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14]],  [[2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9],   [14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6],   [4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14],   [11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3]],  [[12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11],   [10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8],   [9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6],   [4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13]],  [[4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1],   [13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6],   [1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2],   [6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12]],  [[13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7],   [1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2],   [7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8],   [2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11]]]pc1=(57, 49, 41, 33, 25, 17, 9,    1, 58, 50, 42, 34, 26, 18,   10, 2, 59, 51, 43, 35, 27,   19, 11, 3, 60, 52, 44, 36,   63, 55, 47, 39, 31, 33, 15,    7, 62, 54, 46, 38, 30, 22,   14, 6, 61, 53, 45, 37, 29,   21, 13, 5, 28, 20, 12, 4);pc2= (14, 17, 11, 24, 1, 5, 3, 28,   15, 6, 21, 10, 23, 19, 12, 4,    26, 8, 16, 7, 27, 20, 13, 2,    41, 52, 31, 37, 47, 55, 30, 40,    51, 45, 33, 48, 44, 49, 39, 56,    34, 53, 46, 42, 50, 36, 29, 32)d = ( 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1)

2. des.py 加密檔案

#_*_ coding:utf-8 _*_#!/usr/bin/env python#Filename:des.pyfrom desstruct import *import re__all__=['desencode']class DES():  '''des 加密'''  def __init__(self):    pass  #加密  def code(self,from_code,key,code_len,key_len):    output=""    trun_len=0    #將密文和密鑰轉換為二進位    code_string=self._functionCharToA(from_code,code_len)    code_key=self._functionCharToA(key,key_len)    #如果密鑰長度不是16的整數倍則以增加0的方式變為16的整數倍    if code_len%16!=0:      real_len=(code_len/16)*16+16    else:      real_len=code_len    if key_len%16!=0:      key_len=(key_len/16)*16+16    key_len*=4    #每個16進位佔4位    trun_len=4*real_len    #對每64位進行一次加密    for i in range(0,trun_len,64):      run_code=code_string[i:i+64]      l=i%key_len      run_key=code_key[l:l+64]      #64位明文、密鑰初始置換      run_code= self._codefirstchange(run_code)      run_key= self._keyfirstchange(run_key)      #16次迭代      for j in range(16):        #取出明文左右32位        code_r=run_code[32:64]        code_l=run_code[0:32]        #64左右交換        run_code=code_r        #右邊32位擴充置換        code_r= self._functionE(code_r)        #擷取本輪子密鑰        key_l=run_key[0:28]        key_r=run_key[28:56]        key_l=key_l[d[j]:28]+key_l[0:d[j]]        key_r=key_r[d[j]:28]+key_r[0:d[j]]        run_key=key_l+key_r        key_y= self._functionKeySecondChange(run_key)        #異或        code_r= self._codeyihuo(code_r,key_y)        #S盒代替/選擇        code_r= self._functionS(code_r)        #P轉換        code_r= self._functionP(code_r)        #異或        code_r= self._codeyihuo(code_l,code_r)        run_code+=code_r      #32互換      code_r=run_code[32:64]      code_l=run_code[0:32]      run_code=code_r+code_l      #將二進位轉換為16進位、逆初始置換      output+=self._functionCodeChange(run_code)    return output  #異或   def _codeyihuo(self,code,key):    code_len=len(key)    return_list=''    for i in range(code_len):      if code[i]==key[i]:        return_list+='0'      else:        return_list+='1'    return return_list  #密文或明文初始置換  def _codefirstchange(self,code):    changed_code=''    for i in range(64):      changed_code+=code[ip[i]-1]    return changed_code  #密鑰初始置換  def _keyfirstchange (self,key):    changed_key=''    for i in range(56):      changed_key+=key[pc1[i]-1]    return changed_key  #逆初始置換  def _functionCodeChange(self, code):    lens=len(code)/4    return_list=''    for i in range(lens):      list=''      for j in range(4):        list+=code[ip_1[i*4+j]-1]      return_list+="%x" %int(list,2)    return return_list  #擴充置換    def _functionE(self,code):    return_list=''    for i in range(48):      return_list+=code[e[i]-1]    return return_list     #置換P      def _functionP(self,code):    return_list=''    for i in range(32):      return_list+=code[p[i]-1]    return return_list  #S盒代替選擇置換  def _functionS(self, key):    return_list=''    for i in range(8):      row=int( str(key[i*6])+str(key[i*6+5]),2)      raw=int(str( key[i*6+1])+str(key[i*6+2])+str(key[i*6+3])+str(key[i*6+4]),2)      return_list+=self._functionTos(s[i][row][raw],4)    return return_list  #密鑰置換選擇2  def _functionKeySecondChange(self,key):    return_list=''    for i in range(48):      return_list+=key[pc2[i]-1]    return return_list  #將十六進位轉換為二進位字串  def _functionCharToA(self,code,lens):    return_code=''    lens=lens%16    for key in code:      code_ord=int(key,16)      return_code+=self._functionTos(code_ord,4)       if lens!=0:      return_code+='0'*(16-lens)*4    return return_code  #二進位轉換  def _functionTos(self,o,lens):    return_code=''    for i in range(lens):      return_code=str(o>>i &1)+return_code    return return_code#將unicode字元轉換為16進位def tohex(string):  return_string=''  for i in string:    return_string+="%02x"%ord(i)  return return_stringdef tounicode(string):  return_string=''  string_len=len(string)  for i in range(0,string_len,2):    return_string+=chr(int(string[i:i+2],16))  return return_string#入口函數def desencode(from_code,key):  #轉換為16進位  from_code=tohex(from_code)  key=tohex(key)  des=DES()  key_len=len(key)  string_len=len(from_code)      if string_len<1 or key_len<1:    print 'error input'    return False  key_code= des.code(from_code,key,string_len,key_len)  return key_code#測試if __name__ == '__main__':  print desencode('我是12345678劉就是我abcdwfd','0f1571c947劉')#返回密文為: 84148584371a6a1fe99e1da0ce1e34649b88ed15098e8aa4b8eb0bf24885c658

3. 解密檔案

#_*_coding:utf-8_*_#!/usr/bin/env python#Filename:des.pyfrom desstruct import *import re__all__=['desdecode']class DES():  '''解密函數，DES加密與解密的方法相差不大    只是在解密的時候所用的子密鑰與加密的子密鑰相反  '''  def __init__(self):    pass  def decode(self,string,key,key_len,string_len):    output=""    trun_len=0    num=0    #將密文轉換為二進位    code_string=self._functionCharToA(string,string_len)    #擷取字密鑰    code_key=self._getkey(key,key_len)    #如果密鑰長度不是16的整數倍則以增加0的方式變為16的整數倍    real_len=(key_len/16)+1 if key_len%16!=0 else key_len/16    trun_len=string_len*4    #對每64位進行一次加密    for i in range(0,trun_len,64):      run_code=code_string[i:i+64]      run_key=code_key[num%real_len]      #64位明文初始置換      run_code= self._codefirstchange(run_code)      #16次迭代      for j in range(16):        code_r=run_code[32:64]        code_l=run_code[0:32]        #64左右交換         run_code=code_r        #右邊32位擴充置換        code_r= self._functionE(code_r)        #擷取本輪子密鑰        key_y=run_key[15-j]        #異或        code_r= self._codeyihuo(code_r,key_y)        #S盒代替/選擇        code_r= self._functionS(code_r)        #P轉換        code_r= self._functionP(code_r)        #異或        code_r= self._codeyihuo(code_l,code_r)        run_code+=code_r      num+=1      #32互換      code_r=run_code[32:64]      code_l=run_code[0:32]      run_code=code_r+code_l      #將二進位轉換為16進位、逆初始置換      output+=self._functionCodeChange(run_code)    return output  #擷取子密鑰  def _getkey(self,key,key_len):    #將密鑰轉換為二進位    code_key=self._functionCharToA(key,key_len)    a=['']*16    real_len=(key_len/16)*16+16 if key_len%16!=0 else key_len    b=['']*(real_len/16)    for i in range(real_len/16):      b[i]=a[:]    num=0    trun_len=4*key_len    for i in range(0,trun_len,64):      run_key=code_key[i:i+64]      run_key= self._keyfirstchange(run_key)      for j in range(16):        key_l=run_key[0:28]        key_r=run_key[28:56]        key_l=key_l[d[j]:28]+key_l[0:d[j]]        key_r=key_r[d[j]:28]+key_r[0:d[j]]        run_key=key_l+key_r        key_y= self._functionKeySecondChange(run_key)        b[num][j]=key_y[:]      num+=1    return b    #異或                 def _codeyihuo(self,code,key):    code_len=len(key)    return_list=''    for i in range(code_len):      if code[i]==key[i]:        return_list+='0'      else:        return_list+='1'    return return_list  #密文或明文初始置換                   def _codefirstchange(self,code):    changed_code=''    for i in range(64):      changed_code+=code[ip[i]-1]    return changed_code  #密鑰初始置換  def _keyfirstchange (self,key):    changed_key=''    for i in range(56):      changed_key+=key[pc1[i]-1]    return changed_key  #逆初始置換  def _functionCodeChange(self, code):    return_list=''    for i in range(16):      list=''      for j in range(4):        list+=code[ip_1[i*4+j]-1]      return_list+="%x" %int(list,2)    return return_list  #擴充置換    def _functionE(self,code):    return_list=''    for i in range(48):      return_list+=code[e[i]-1]    return return_list     #置換P    def _functionP(self,code):    return_list=''    for i in range(32):      return_list+=code[p[i]-1]    return return_list  #S盒代替選擇置換    def _functionS(self, key):    return_list=''    for i in range(8):      row=int( str(key[i*6])+str(key[i*6+5]),2)      raw=int(str( key[i*6+1])+str(key[i*6+2])+str(key[i*6+3])+str(key[i*6+4]),2)      return_list+=self._functionTos(s[i][row][raw],4)    return return_list  #密鑰置換選擇2  def _functionKeySecondChange(self,key):    return_list=''    for i in range(48):      return_list+=key[pc2[i]-1]    return return_list  #將十六進位轉換為二進位字串  def _functionCharToA(self,code,lens):    return_code=''    lens=lens%16    for key in code:      code_ord=int(key,16)      return_code+=self._functionTos(code_ord,4)    if lens!=0:      return_code+='0'*(16-lens)*4    return return_code  #二進位轉換  def _functionTos(self,o,lens):    return_code=''    for i in range(lens):      return_code=str(o>>i &1)+return_code    return return_code#將unicode字元轉換為16進位def tohex(string):  return_string=''  for i in string:    return_string+="%02x"%ord(i)  return return_stringdef tounicode(string):  return_string=''  string_len=len(string)  for i in range(0,string_len,2):    return_string+=chr(int(string[i:i+2],16))  return return_string#入口函數def desdecode(from_code,key):  key=tohex(key)  des=DES()  key_len=len(key)  string_len=len(from_code)  if string_len%16!=0:    return False  if string_len<1 or key_len<1:    return False  key_code= des.decode(from_code,key,key_len,string_len)  return tounicode(key_code)#測試if __name__ == '__main__':  print desdecode('84148584371a6a1fe99e1da0ce1e34649b88ed15098e8aa4b8eb0bf24885c658','0f1571c947劉'

解密後為: 我是12345678劉就是我abcdwfd

希望本文所述對大家的Python程式設計有所協助。

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