DES的加密與解密演算法（Python實現）

加密解密演算法 Python · 發表 2019-03-22 00:16:00

摘要： DES的加密與解密演算法（Python實現）密碼學實驗：實現了DES的簡單的加密和解密演算法，DES演算法的相關資料網上很多，這裡不再贅述，僅僅貼出原始碼給大家分享，原始碼中包含很多漢字註釋，相信大家都是可以讀懂...

密碼學實驗： 實現了DES的簡單的加密和解密演算法，DES演算法的相關資料網上很多，這裡不再贅述，僅僅貼出原始碼給大家分享，原始碼中包含很多漢字註釋，相信大家都是可以讀懂的。

為了方便閱讀和理解DES演算法的原理，這裡我將程式碼進行了模組化，分為了四個模組：金鑰生成模組、F函式模組、DES加密模組、DES解密模組。

注：DES的加密演算法和解密演算法幾乎是一模一樣的，僅僅是金鑰的使用順序不同，所以模組的程式碼也幾乎沒有什麼區別。輸入輸出要求是16個十六進位制的字元，剛好是64bit！

轉載請註明出處：https://www.cnblogs.com/wangyanzhong123/p/10575739.html

金鑰生成模組：

 1 MaxTime = 16
 2#生成子金鑰的置換表1，將64位的金鑰轉換為56位
 3 key_table1=[ 57, 49, 41, 33, 25, 17,9,
 41, 58, 50, 42, 34, 26, 18,
 510,2, 59, 51, 43, 35, 27,
 619, 11,3, 60, 52, 44, 36,
 763, 55, 47, 39, 31, 23, 15,
 87, 62, 54, 46, 38, 30, 22,
 914,6, 61, 53, 45, 37, 29,
1021, 13,5, 28, 20, 12,4 ]
11#生成子金鑰的置換表2，將56位的金鑰轉換為48位
12 key_table2=[ 14, 17, 11, 24,1,5,
133, 28, 15,6, 21, 10,
1423, 19, 12,4, 26,8,
1516,7, 27, 20, 13,2,
1641, 52, 31, 37, 47, 55,
1730, 40, 51, 45, 33, 48,
1844, 49, 39, 56, 34, 53,
1946, 42, 50, 36, 29, 32 ]
20 
21 def Listmove(l, step):#將列表中的元素迴圈左移
22return l[step:] + l[:step]
23 
24 def Subkey(key):#生成子金鑰
25keyresult = []
26key0 = [0 for i in range(56)]
27 
28for i in range(len(key_table1)):
29key0[i] = key[key_table1[i]-1]
30 
31#生成16個金鑰
32for i in range(MaxTime):
33key1 = [0 for i in range(48)]
34#確定每次左移的步數
35if (i == 0 or i == 1 or i == 8 or i == 15):
36step = 1
37else:
38step = 2
39#分成兩組
40tmp1 = key0[0:28]
41tmp2 = key0[28:56]
42#迴圈左移
43tmp1 = Listmove(tmp1, step)
44tmp2 = Listmove(tmp2, step)
45#左右連線
46key0 = tmp1 + tmp2
47#置換選擇
48for i in range(len(key_table2)):
49key1[i] = key0[key_table2[i]-1]
50#生成金鑰
51keyresult.append(key1)
52#返回的是一個集合包含了每次的金鑰
53return keyresult

F函式模組：

1 MaxTime = 16
2 #IP置換表
3 IP_table=[58, 50, 42, 34, 26, 18, 10, 2,
460, 52, 44, 36, 28, 20, 12, 4,
562, 54, 46, 38, 30, 22, 14, 6,
664, 56, 48, 40, 32, 24, 16, 8,
757, 49, 41, 33, 25, 17,9, 1,
859, 51, 43, 35, 27, 19, 11, 3,
961, 53, 45, 37, 29, 21, 13, 5,
 1063, 55, 47, 39, 31, 23, 15, 7 ]
 11 #逆IP置換表
 12 Inv_IP_table=[40,8, 48, 16, 56, 24, 64, 32,
 1339,7, 47, 15, 55, 23, 63, 31,
 1438,6, 46, 14, 54, 22, 62, 30,
 1537,5, 45, 13, 53, 21, 61, 29,
 1636,4, 44, 12, 52, 20, 60, 28,
 1735,3, 43, 11, 51, 19, 59, 27,
 1834,2, 42, 10, 50, 18, 58, 26,
 1933,1, 41,9, 49, 17, 57, 25 ]
 20 #S盒中的S1盒
 21 S1=[14,4, 13,1,2, 15, 11,8,3, 10,6, 12,5,9,0,7,
 220, 15,7,4, 14,2, 13,1, 10,6, 12, 11,9,5,3,8,
 234,1, 14,8, 13,6,2, 11, 15, 12,9,7,3, 10,5,0,
 2415, 12,8,2,4,9,1,7,5, 11,3, 14, 10,0,6, 13 ]
 25 #S盒中的S2盒
 26 S2=[15,1,8, 14,6, 11,3,4,9,7,2, 13, 12,0,5, 10,
 273, 13,4,7, 15,2,8, 14, 12,0,1, 10,6,9, 11,5,
 280, 14,7, 11, 10,4, 13,1,5,8, 12,6,9,3,2, 15,
 2913,8, 10,1,3, 15,4,2, 11,6,7, 12,0,5, 14,9 ]
 30 #S盒中的S3盒
 31 S3=[10,0,9, 14,6,3, 15,5,1, 13, 12,7, 11,4,2,8,
 3213,7,0,9,3,4,6, 10,2,8,5, 14, 12, 11, 15,1,
 3313,6,4,9,8, 15,3,0, 11,1,2, 12,5, 10, 14,7,
 341, 10, 13,0,6,9,8,7,4, 15, 14,3, 11,5,2, 12 ]
 35 #S盒中的S4盒
 36 S4=[ 7, 13, 14,3,0,6,9, 10,1,2,8,5, 11, 12,4, 15,
 3713,8, 11,5,6, 15,0,3,4,7,2, 12,1, 10, 14,9,
 3810,6,9,0, 12, 11,7, 13, 15,1,3, 14,5,2,8,4,
 393, 15,0,6, 10,1, 13,8,9,4,5, 11, 12,7,2, 14 ]
 40 #S盒中的S5盒
 41 S5=[ 2, 12,4,1,7, 10, 11,6,8,5,3, 15, 13,0, 14,9,
 4214, 11,2, 12,4,7, 13,1,5,0, 15, 10,3,9,8,6,
 434,2,1, 11, 10, 13,7,8, 15,9, 12,5,6,3,0, 14,
 4411,8, 12,7,1, 14,2, 13,6, 15,0,9, 10,4,5,3 ]
 45 #S盒中的S6盒
 46 S6=[12,1, 10, 15,9,2,6,8,0, 13,3,4, 14,7,5, 11,
 4710, 15,4,2,7, 12,9,5,6,1, 13, 14,0, 11,3,8,
 489, 14, 15,5,2,8, 12,3,7,0,4, 10,1, 13, 11,6,
 494,3,2, 12,9,5, 15, 10, 11, 14,1,7,6,0,8, 13 ]
 50 #S盒中的S7盒
 51 S7=[ 4, 11,2, 14, 15,0,8, 13,3, 12,9,7,5, 10,6,1,
 5213,0, 11,7,4,9,1, 10, 14,3,5, 12,2, 15,8,6,
 531,4, 11, 13, 12,3,7, 14, 10, 15,6,8,0,5,9,2,
 546, 11, 13,8,1,4, 10,7,9,5,0, 15, 14,2,3, 12]
 55 #S盒中的S8盒
 56 S8=[13,2,8,4,6, 15, 11,1, 10,9,3, 14,5,0, 12,7,
 571, 15, 13,8, 10,3,7,4, 12,5,6, 11,0, 14,9,2,
 587, 11,4,1,9, 12, 14,2,0,6, 10, 13, 15,3,5,8,
 592,1, 14,7,4, 10,8, 13, 15, 12,9,0,3,5,6, 11 ]
 60 # S盒
 61 S=[S1,S2,S3,S4,S5,S6,S7,S8]
 62 #用於對資料進行擴充套件置換，將32bit資料擴充套件為48bit
 63 extend_table=[32,1,2,3,4,5,
 644,5,6,7,8,9,
 658,9, 10, 11, 12, 13,
 6612, 13, 14, 15, 16, 17,
 6716, 17, 18, 19, 20, 21,
 6820, 21, 22, 23, 24, 25,
 6924, 25, 26, 27, 28, 29,
 7028, 29, 30, 31, 32,1 ]
 71 #P盒
 72 P_table=[ 16,7, 20, 21, 29, 12, 28, 17,
 731, 15, 23, 26,5, 18, 31, 10,
 742,8, 24, 14, 32, 27,3,9,
 7519, 13, 30,6, 22, 11,4, 25 ]
 76 
 77 def int2bit(n):#0~15整數轉位元
 78a=[]
 79for i in range(0,4):
 80a.insert(0,str(n%2))
 81n=int(n/2)
 82return a
 83 
 84 #IP置換部分，op為0表示正置換，op為1表示逆置換
 85 def IP(text, op):
 86tmp = [0 for i in range(64)]
 87if op == 0:
 88for i in range(64):
 89tmp[i] = text[IP_table[i]-1]
 90return tmp
 91if op == 1:
 92for i in range(64):
 93tmp[i] = text[Inv_IP_table[i]-1]
 94return tmp
 95 #進行擴充套件，將32位擴充套件為48位
 96 def Extend(text):
 97extend = [0 for i in range(48)]
 98for i in range(48):
 99extend[i] = text[extend_table[i] - 1]
100return extend
101 
102 #S盒變換部分
103 def S_replace(text):
104Sresult = [0 for k in range(32)]
105for k in range(8):
106row = 2*int(text[k*6]) + int(text[k*6+5])
107column = 8*int(text[k*6+1]) + 4*int(text[k*6+2]) + 2*int(text[k*6+3]) + int(text[k*6+4])
108tmp = S[k][row*16+column]
109 
110for i in range(4):
111Sresult[4*k + i] = int2bit(tmp)[i]
112return Sresult
113 #P置換部分
114 def P_replace(text):
115Presult = [0 for i in range(32)]
116for i in range(32):
117Presult[i] = text[P_table[i]-1]
118return Presult
119 #異或運算
120 def Xor(bit1, bit2):
121Xorresult = [0 for i in range(len(bit1))]
122for i in range(len(bit1)):
123Xorresult[i] = str(int(bit1[i]) ^ int(bit2[i]))
124return Xorresult

DES加密模組：

 1 import CreateSubkey as cs
 2 import F_function as f
 3 #十六進位制轉二進位制位元串
 4 def Hex2bin(text):
 5result = []
 6for i in range(len(text)):
 7result.extend(f.int2bit(int(text[i],16)))
 8return result
 9 #二進位制位元串轉十六進位制
10 def bin2Hex(text):
11result = []
12q = len(text)//4
13for i in range(q):
14dec = int(text[4*i])*8 + int(text[4*i+1])*4 + int(text[4*i+2])*2 + int(text[4*i+3])*1
15x = hex(dec)[2:].upper()
16result.extend(x)
17rs = ''.join(result)
18return rs
19 #按照DES演算法的流程圖進行運算
20 def Encryption(text, key):
21keylist = cs.Subkey(keybit)
22text1 = f.IP(text, 0)#IP置換
23L = [text1[i] for i in range(32)]
24R = [text1[i] for i in range(32,64)]
25for i in range(16):
26tmp = R
27tmp = f.Extend(tmp)
28tmp = f.Xor(tmp, keylist[i])
29tmp = f.S_replace(tmp)
30tmp = f.P_replace(tmp)
31tmp = f.Xor(tmp, L)
32L = R
33R = tmp
34L,R = R,L
35ctext = L
36ctext.extend(R)
37ctext = f.IP(ctext, 1)
38return bin2Hex(ctext)
39 
40 if __name__ == '__main__':
41plaintext = input('請輸入用十六進位制表示的明文：') 
42key = input('請輸入用十六進位制表示的金鑰：')
43ptext = Hex2bin(plaintext)
44keybit = Hex2bin(key)
45print('輸出的密文為：' + Encryption(ptext, keybit))

DES解密模組：

 1 import CreateSubkey as cs
 2 import F_function as f
 3 #十六進位制轉二進位制位元串
 4 def Hex2bin(text):
 5result = []
 6for i in range(len(text)):
 7result.extend(f.int2bit(int(text[i],16)))
 8return result
 9 #二進位制位元串轉十六進位制
10 def bin2Hex(text):
11result = []
12q = len(text)//4
13for i in range(q):
14dec = int(text[4*i])*8 + int(text[4*i+1])*4 + int(text[4*i+2])*2 + int(text[4*i+3])*1
15x = hex(dec)[2:].upper()
16result.extend(x)
17rs = ''.join(result)
18return rs
19 
20 def Encryption(text, key):
21keylist = cs.Subkey(keybit)
22text1 = f.IP(text, 0)#IP置換
23L = [text1[i] for i in range(32)]
24R = [text1[i] for i in range(32,64)]
25for i in range(16):
26tmp = R
27tmp = f.Extend(tmp)
28tmp = f.Xor(tmp, keylist[15-i])
29tmp = f.S_replace(tmp)
30tmp = f.P_replace(tmp)
31tmp = f.Xor(tmp, L)
32L = R
33R = tmp
34L,R = R,L
35ctext = L
36ctext.extend(R)
37ctext = f.IP(ctext, 1)
38return bin2Hex(ctext)
39 
40 if __name__ == '__main__':
41plaintext = input('請輸入用十六進位制表示的密文：') 
42key = input('請輸入用十六進位制表示的金鑰：')
43ptext = Hex2bin(plaintext)
44keybit = Hex2bin(key)
45print('輸出的明文為：' + Encryption(ptext, keybit))

DES的加密與解密演算法（Python實現）

金鑰生成模組：

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