本文实例讲述了python实现DES加密解密方法。分享给大家供大家参考。具体分析如下：

实现功能：加密中文等字符串

密钥与明文可以不等长

这里只贴代码，加密过程可以自己百度，此处python代码没有优化

1. desstruct.py DES加密中要使用的结构体

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 加密文件

#_*_ 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

3. 解密文件

#_*_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'

解密后为: 我是12345678刘就是我abcdwfd

希望本文所述对大家的Python程序设计有所帮助。

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