python实现DES加密解密方法实例详解

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)

#_*_ coding:utf-8 _*_
#!/usr/bin/env python
#Filename:des.py
from 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
 #将密文和密钥转换为二进制
 code_string=self._functionCharToA(from_code,code_len)
 code_key=self._functionCharToA(key,key_len)
 #如果密钥长度不是16的整数倍则以增加0的方式变为16的整数倍
 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
 #每个16进制占4位
 trun_len=4*real_len
 #对每64位进行一次加密
 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、密钥初始置换
 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左右交换
 run_code=code_r
 #右边32位扩展置换
 code_r= self._functionE(code_r)
 #获取本轮子密钥
 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)
 #异或
 code_r= self._codeyihuo(code_r,key_y)
 #S盒代替/选择
 code_r= self._functionS(code_r)
 #P转换
 code_r= self._functionP(code_r)
 #异或
 code_r= self._codeyihuo(code_l,code_r)
 run_code+=code_r
 #32互换
 code_r=run_code[32:64]
 code_l=run_code[0:32]
 run_code=code_r+code_l
 #将二进制转换为16进制、逆初始置换
 output+=self._functionCodeChange(run_code)
 return output
 #异或 
 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
 #密文或明文初始置换
 def _codefirstchange(self,code):
 changed_code=''
 for i in range(64):
 changed_code+=code[ip[i]-1]
 return changed_code
 #密钥初始置换
 def _keyfirstchange (self,key):
 changed_key=''
 for i in range(56):
 changed_key+=key[pc1[i]-1]
 return changed_key
 #逆初始置换
 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
 #扩展置换 
 def _functionE(self,code):
 return_list=''
 for i in range(48):
 return_list+=code[e[i]-1]
 return return_list 
 #置换P 
 def _functionP(self,code):
 return_list=''
 for i in range(32):
 return_list+=code[p[i]-1]
 return return_list
 #S盒代替选择置换
 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
 #密钥置换选择2
 def _functionKeySecondChange(self,key):
 return_list=''
 for i in range(48):
 return_list+=key[pc2[i]-1]
 return return_list
 #将十六进制转换为二进制字符串
 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
 #二进制转换
 def _functionTos(self,o,lens):
 return_code=''
 for i in range(lens):
 return_code=str(o>>i &1)+return_code
 return return_code
#将unicode字符转换为16进制
def tohex(string):
 return_string=''
 for i in string:
 return_string+="%02x"%ord(i)
 return return_string
def 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
#入口函数
def desencode(from_code,key):
 #转换为16进制
 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
#测试
if __name__ == '__main__':
 print desencode('我是12345678刘就是我abcdwfd','0f1571c947刘')
#返回密文为: 84148584371a6a1fe99e1da0ce1e34649b88ed15098e8aa4b8eb0bf24885c658

#_*_coding:utf-8_*_
#!/usr/bin/env python
#Filename:des.py
from desstruct import *
import re
__all__=['desdecode']
class DES():
 '''解密函数，DES加密与解密的方法相差不大
 只是在解密的时候所用的子密钥与加密的子密钥相反
 '''
 def __init__(self):
 pass
 def decode(self,string,key,key_len,string_len):
 output=""
 trun_len=0
 num=0
 #将密文转换为二进制
 code_string=self._functionCharToA(string,string_len)
 #获取字密钥
 code_key=self._getkey(key,key_len)
 #如果密钥长度不是16的整数倍则以增加0的方式变为16的整数倍
 real_len=(key_len/16)+1 if key_len%16!=0 else key_len/16
 trun_len=string_len*4
 #对每64位进行一次加密
 for i in range(0,trun_len,64):
 run_code=code_string[i:i+64]
 run_key=code_key[num%real_len]
 #64位明文初始置换
 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左右交换 
 run_code=code_r
 #右边32位扩展置换
 code_r= self._functionE(code_r)
 #获取本轮子密钥
 key_y=run_key[15-j]
 #异或
 code_r= self._codeyihuo(code_r,key_y)
 #S盒代替/选择
 code_r= self._functionS(code_r)
 #P转换
 code_r= self._functionP(code_r)
 #异或
 code_r= self._codeyihuo(code_l,code_r)
 run_code+=code_r
 num+=1
 #32互换
 code_r=run_code[32:64]
 code_l=run_code[0:32]
 run_code=code_r+code_l
 #将二进制转换为16进制、逆初始置换
 output+=self._functionCodeChange(run_code)
 return output
 #获取子密钥
 def _getkey(self,key,key_len):
 #将密钥转换为二进制
 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 
 #异或 
 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
 #密文或明文初始置换 
 def _codefirstchange(self,code):
 changed_code=''
 for i in range(64):
 changed_code+=code[ip[i]-1]
 return changed_code
 #密钥初始置换
 def _keyfirstchange (self,key):
 changed_key=''
 for i in range(56):
 changed_key+=key[pc1[i]-1]
 return changed_key
 #逆初始置换
 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
 #扩展置换 
 def _functionE(self,code):
 return_list=''
 for i in range(48):
 return_list+=code[e[i]-1]
 return return_list 
 #置换P 
 def _functionP(self,code):
 return_list=''
 for i in range(32):
 return_list+=code[p[i]-1]
 return return_list
 #S盒代替选择置换 
 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
 #密钥置换选择2
 def _functionKeySecondChange(self,key):
 return_list=''
 for i in range(48):
 return_list+=key[pc2[i]-1]
 return return_list
 #将十六进制转换为二进制字符串
 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
 #二进制转换
 def _functionTos(self,o,lens):
 return_code=''
 for i in range(lens):
 return_code=str(o>>i &1)+return_code
 return return_code
#将unicode字符转换为16进制
def tohex(string):
 return_string=''
 for i in string:
 return_string+="%02x"%ord(i)
 return return_string
def 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
#入口函数
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)
#测试
if __name__ == '__main__':
 print desdecode('84148584371a6a1fe99e1da0ce1e34649b88ed15098e8aa4b8eb0bf24885c658','0f1571c947刘'