-
Notifications
You must be signed in to change notification settings - Fork 0
/
Des.py
266 lines (224 loc) · 11.6 KB
/
Des.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
# -*- coding: utf8 -*-
import base64
import random,string
# 初始置换IP
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]
# Key 初始置换选择1
CP_1 = [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]
# KEY 置换选择2
CP_2 = [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]
# 数据块 扩展置换
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]
# SBOX
S_BOX = [
[[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],
]
]
# P盒置换
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]
# 初始逆置换
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]
# 确定每轮产生键的移位矩阵
SHIFT = [1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1]
def string_to_bit_array(text): # 字符串-->bit数组
array = list()
for char in text:
binval = binvalue(char, 8) # 获得每个字符的二进制
array.extend([int(x) for x in list(binval)])
return array
def bit_array_to_string(array): # bit数组-->字符串
res = ''.join([chr(int(y, 2)) for y in [''.join([str(x) for x in bytes]) for bytes in nsplit(array, 8)]])
return res
def binvalue(val, bitsize): # 以给定大小的字符返回二进制值
binval = bin(val)[2:] if isinstance(val, int) else bin(ord(val))[2:]
if len(binval) > bitsize:
raise Exception("binary value larger than the expected size")
while len(binval) < bitsize:
binval = "0" + binval
return binval
def nsplit(s, n): # 将列表拆分为大小为'n'的子列表
return [s[k:k + n] for k in range(0, len(s), n)]
def getRandomString(slen=8): # 获得key的随机序列
return ''.join(random.sample(string.ascii_letters + string.digits, slen))
ENCRYPT = 1
DECRYPT = 0
class Des():
def __init__(self):
self.password = None # 存放初始key
self.text = None # 存放明文
self.keys = list() # 存放key值列表集合
def run(self, key, text, action, padding):
if len(key) < 8:
raise Exception("Key Should be 8 bytes long")
elif len(key) > 8:
key = key[:8] # 如果key的长度大于8，则取其前8位字节
self.password = key
self.text = text
if padding and action == ENCRYPT:
self.addPadding()
elif len(self.text) % 8 != 0: # 数据的大小一定是 8bytes 大小的倍数
raise Exception("Data size should be multiple of 8")
self.generatekeys() # 统计计算所有的key值，存入keys列表
text_blocks = nsplit(self.text, 8) # 数据的分片每8个字节一组
result = list()
for block in text_blocks: # 遍历所有数据块
block = string_to_bit_array(block)
block = self.permut(block, IP) # 数据块的初始置换
g, d = nsplit(block, 32) # 数据块分片 g(LEFT), d(RIGHT)
tmp = None
for i in range(16): # 16轮循环
d_e = self.expand(d, E) # d(RIGHT)的扩展 32bit-->48bit
if action == ENCRYPT:
tmp = self.xor(self.keys[i], d_e)
else:
tmp = self.xor(self.keys[15 - i], d_e) # 如果是解密的话先使用最后的key
tmp = self.substitute(tmp) # S盒代换 48bit-->32bit
tmp = self.permut(tmp, P) # P盒置换
tmp = self.xor(g, tmp)
g = d
d = tmp
result += self.permut(d + g, IP_1) # 数据块的初始逆置换
final_res = bit_array_to_string(result)
if padding and action == DECRYPT:
return self.removePadding(final_res) # 如果解密和填充为真，则删除填充
else:
return final_res
def substitute(self, d_e): # S盒代换
subblocks = nsplit(d_e, 6) # 将位数组分割为6位的子列表
result = list()
for i in range(len(subblocks)): # 遍历子列表
block = subblocks[i]
row = int(str(block[0]) + str(block[5]), 2) # 得到第一位和最后一个位表示的行
column = int(''.join([str(x) for x in block[1:][:-1]]), 2) # 得到第二、三、四、五位表示的列
val = S_BOX[i][row][column] # 取为本轮分配的SBOX[i]中的值
bin = binvalue(val, 4) # 将值转换为二进制
result += [int(x) for x in bin] # 将二进制值添加到结果列表中
return result
def permut(self, block, table): # 置换(本程序中充当基本置换、压缩置换的角色)
return [block[x - 1] for x in table]
def expand(self, block, table): # 扩展置换
return [block[x - 1] for x in table]
def xor(self, t1, t2): # 应用xor并返回结果列表
return [x ^ y for x, y in zip(t1, t2)]
def generatekeys(self): # 统计计算所有key值的算法
self.keys = []
key = string_to_bit_array(self.password)
key = self.permut(key, CP_1) # 置换选择1 初始化key 64bit-->56bit
g, d = nsplit(key, 28) # 分片 (g->LEFT),(d->RIGHT)
for i in range(16): # 16轮循环
g, d = self.shift(g, d, SHIFT[i]) # (g->LEFT),(d->RIGHT)分别进行移位操作
tmp = g + d # 合并 28bit+28bit-->56bit
self.keys.append(self.permut(tmp, CP_2))# 置换选择2 56bit-->48bit
def shift(self, g, d, n): # 每轮key值产生所需的函数
return g[n:] + g[:n], d[n:] + d[:n]
def addPadding(self): # 使用 PKCS5 进行数据的填充,不管是否是BlockSize的整数倍都需要进行填充
pad_len = 8 - (len(self.text) % 8)
self.text += pad_len * chr(pad_len)
def removePadding(self, data): # 删除纯文本的填充
pad_len = ord(data[-1])
return data[:-pad_len]
def encrypt(self, key, text, padding): # DES 加密函数
return self.run(key, text, ENCRYPT, padding)
def decrypt(self, key, text, padding): # DES 解密函数
return self.run(key, text, DECRYPT, padding)
if __name__ == '__main__':
key = getRandomString()
with open('text.txt','r+') as fr:
text = (fr.read()) # 从 'text.txt' 文件中读取加密文本
D = Des()
C = (base64.b64encode((D.encrypt(key, text, True)).encode("utf8"))).decode()#加密
C1 = (base64.b64decode(C)).decode()
P = D.decrypt(key, C1, True) # 解密
with open('key.txt','w+') as fwk: # 存储密钥
fwk.write(key)
with open('ciphertext.txt','w+') as fwc: # 存储密文
fwc.write(C)
with open('plaintext.txt','w+') as fwp: # 存储明文
fwp.writelines(P)
print('********************* Des Encryption and Decryption *********************')
print('* *')
print('* *')
print('* *')
print('* Key: 存储于 < key.txt > 文件中. *')
print('* *')
print('* Ciphertext: 存储于 < ciphertext.txt > 文件中. *')
print('* *')
print('* Plaintext: 存储于 < plaintext.txt > 文件中. *')
print('* *')
print('* *')
print('* *')
print('*************************************************************************')