NEKO

Python-DES

2017/12/15

python3实现DES加解密(愚蠢的选择)

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#-*- coding:utf-8 -*-
import time
#IP置换表
IP_table=[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]
#逆IP置换表
_IP_table=[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]
#S盒中的S1盒
S1=[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]
#S盒中的S2盒
S2=[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]
#S盒中的S3盒
S3=[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]
#S盒中的S4盒
S4=[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]
#S盒中的S5盒
S5=[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]
#S盒中的S6盒
S6=[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]
#S盒中的S7盒
S7=[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]
#S盒中的S8盒
S8=[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]
# S盒
S=[S1,S2,S3,S4,S5,S6,S7,S8]
#P盒
P_table=[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]
#压缩置换表1,不考虑每字节的第8位,将64位密钥减至56位。然后进行一次密钥置换。
yasuo1_table=[ 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, 23, 15,
7, 62, 54, 46, 38, 30, 22,
14, 6, 61, 53, 45, 37, 29,
21, 13, 5, 28, 20, 12, 4]
#压缩置换表2,用于将循环左移和右移后的56bit密钥压缩为48bit
yasuo2_table=[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]
#用于对数据进行扩展置换,将32bit数据扩展为48bit
extend_table=[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]

#长度为8的明文转换为64位的2进制字符串
def Str2Bin(str):
temp=[]
for i in str:
temp.append(bin(ord(i)))
result=''
for i in temp:
binstr=i[2:]
while len(binstr)!=8:
binstr='0'+binstr
result+=binstr
return result

#2进制字符窜转换为ascii字符
def Bin2Ascii(binstr):
result = ''
for i in range(0, len(binstr), 8):
result += chr(int(binstr[i:i + 8], 2))
return result

#扩展R为48位
def ExtendR(str):
R=''
for i in extend_table:
R+=str[i-1]
return R

#去掉key的奇偶校验位,64位压缩到56位
def YasuoKey(key):
result=''
for i in yasuo1_table:
result+=key[i-1]
return result

#左移一位
def LeftMove1(list):
temp=list[0]
for i in range(1,28):
list[i-1]=list[i]
list[27]=temp
return list

#左移两位
def LeftMove2(list):
temp1=list[0]
temp2=list[1]
for i in range(2,28):
list[i-2]=list[i]
list[26]=temp1
list[27]=temp2
return list

#56位密钥压缩为48位子密钥
def CreateChildkey(Lkey,Rkey):
result=''
Lstr=''
Rstr=''
for i in range(28):
Lstr+=Lkey[i]
Rstr+=Rkey[i]
str=Lstr+Rstr
for i in yasuo2_table:
result+=str[i-1]
return result

#生成16轮密钥
def CreateKey(key):
result=[]#存储16轮的密钥
Binkey=Str2Bin(key)
Lkey=[]
Rkey=[]
for i in range(28):
Lkey.append(YasuoKey(Binkey)[i])
Rkey.append(YasuoKey(Binkey)[i+28])
for i in range(16):
if i==0 or i==1 or i==8 or i==15: #第0,1,8,15轮左移1位,其余左移2位
Lkey=LeftMove1(Lkey)
Rkey=LeftMove1(Rkey)
else:
Lkey = LeftMove2(Lkey)
Rkey = LeftMove2(Rkey)
result.append(CreateChildkey(Lkey,Rkey))
return result

#S盒变换
def Sconvert(xorR):
xorRList=[]
result=''
for i in range(0,len(xorR),6):
xorRList.append(xorR[i:i+6])
for i in range(len(xorRList)):
x = int(xorRList[i][:2], 2)
y = int(xorRList[i][2:], 2)
newstr=bin(S[i][x * 16 + y])[2:]
while len(newstr)!=4: #不足4位补0
newstr='0'+newstr
result+=newstr
return result

#P盒变换
def Pconvert(sR):
result=''
for i in range(32):
result+=sR[P_table[i]-1]
return result

#DES加密
def DESEncode(plain,key):
KeyList=CreateKey(key)
cipher=''
while len(plain)%8!=0:
plain+=' '

# print('初始二进制明文为:')

plainList=[]
for i in range(0,len(plain),8):
plainList.append(plain[i:i+8])
for plain in plainList:
Binstr = Str2Bin(plain)
# print(Binstr,end='')
result=''
L=''
R=''
for i in range(32): #初始置换IP并分成L,R两份
L+=Binstr[IP_table[i]-1]
R+=Binstr[IP_table[i+32]-1]

for i in range(16): #16轮变换
tempL=L
L=R
extendR=ExtendR(R) #扩展R为48位
R=''
xorR=''
for j in range(48): #R与密钥异或
if extendR[j]!=KeyList[i][j]:
xorR+='1'
else:
xorR+='0'
sR=Sconvert(xorR) #s盒变换
pR=Pconvert(sR) #p盒变换

for j in range(32): #与L异或
if pR[j]!=tempL[j]:
R+='1'
else:
R+='0'

for i in range(64): #(L与R换位后)逆变换
result+=(R+L)[_IP_table[i]-1]

cipher+=result
cipher=Bin2Ascii(cipher) #密文转换为ascii字符
# print('密文为:\n%s'%cipher)
return cipher

#DES解密 (把密钥使用顺序倒过来即可)
def DESdecode(cipher,key):
KeyList = CreateKey(key)
cipherBin = ''
plain=''
for i in cipher:
temp = bin(ord(i))[2:]
while len(temp) != 8:
temp = '0' + temp
cipherBin += temp

# print('cipherbin:/n%s'%cipherBin)

for l in range(0,len(cipherBin),64):
Binstr = cipherBin[l:l+64]
result = ''
L = ''
R = ''
for i in range(32):
L += Binstr[IP_table[i] - 1]
R += Binstr[IP_table[i + 32] - 1]

for i in range(15,-1,-1):
tempL = L
L = R
extendR = ExtendR(R)
R = ''
xorR = ''
for j in range(48):
if extendR[j] != KeyList[i][j]:
xorR += '1'
else:
xorR += '0'
sR = Sconvert(xorR)
pR = Pconvert(sR)

for j in range(32):
if pR[j] != tempL[j]:
R += '1'
else:
R += '0'

for i in range(64):
result += (R+L)[_IP_table[i] - 1]

plain += result
plain = Bin2Ascii(plain)
# print("解密的明文为:\n%s"%plain)
return plain
if __name__=='__main__':
while True:
choice=input("加密请输入:1\n解密请输入:2\n退出请按:3\n")
if choice=='1':
key=input('请输入8位密钥:\n')
while len(key)!=8:
key = input('请输入8位密钥!:\n')
filename1=input('请输入当前目录下要加密的文本的名称:\n')
filename2=input('请输入存储密文文本的名称:\n')
print('加密开始,wait...\n')
stime = time.time()

f1=open(filename1,'r',encoding='utf-8')
plain=f1.read()

cipher=DESEncode(plain,key)
f2=open(filename2,'w',encoding='utf-8')
f2.write(cipher)

etime = time.time()
print('加密完成,耗时%ds,结果存放在%s中'%((etime-stime),filename2))
f1.close()
f2.close()
elif choice=='2':
key = input('请输入8位密钥:\n')
while len(key) != 8:
key = input('请输入8位密钥!:\n')
filename1 = input('请输入当前目录下要解密的文本名称:\n')
filename2 = input('请输入存储明文文本的名称:\n')
print('解密开始,wait...\n')
stime = time.time()

f1 = open(filename1, 'r',encoding='utf-8')
cipher = f1.read()

plain = DESdecode(cipher, key)
f2 = open(filename2, 'w',encoding='utf-8')
f2.write(plain)

etime = time.time()
print('解密完成,耗时%ds,结果存放在%s中' % ((etime - stime),filename2))
f1.close()
f2.close()
elif choice=='3':
break
else:
print("请输入正确的序号!")

原文作者: n3k0

发表日期: December 15th 2017, 8:54:29

发出嘶吼: 没有魔夜2玩我要死了

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