DES加密

DES加密解释见qq空间

http://user.qzone.qq.com/240011742/infocenter#!app=2&via=QZ.HashRefresh&pos=1365766516

这里只给出代码（STL版本）：

1 //des.h
  2 #pragma once
  3 #include <bitset>
  4 #include <iostream>
  5 
  6 const int ip[] = { 
  7     58, 50, 42, 34, 26, 18, 10, 2, 
  8     60, 52, 44, 36, 28, 20, 12, 4, 
  9     62, 54, 46, 38, 30, 22, 14, 6, 
 10     64, 56, 48, 40, 32, 24, 16, 8, 
 11     57, 49, 41, 33, 25, 17, 9, 1, 
 12     59, 51, 43, 35, 27, 19, 11, 3, 
 13     61, 53, 45, 37, 29, 21, 13, 5, 
 14     63, 55, 47, 39, 31, 23, 15, 7 
 15 };
 16 
 17 const int fp[] = { 
 18     40, 8, 48, 16, 56, 24, 64, 32, 
 19     39, 7, 47, 15, 55, 23, 63, 31, 
 20     38, 6, 46, 14, 54, 22, 62, 30, 
 21     37, 5, 45, 13, 53, 21, 61, 29, 
 22     36, 4, 44, 12, 52, 20, 60, 28, 
 23     35, 3, 43, 11, 51, 19, 59, 27, 
 24     34, 2, 42, 10, 50, 18, 58, 26, 
 25     33, 1, 41, 9, 49, 17, 57, 25 
 26 }; 
 27 
 28 const int ei[] = { 
 29     32, 1, 2, 3, 4, 5, 
 30     4, 5, 6, 7, 8, 9, 
 31     8, 9, 10, 11, 12, 13, 
 32     12, 13, 14, 15, 16, 17, 
 33     16, 17, 18, 19, 20, 21, 
 34     20, 21, 22, 23, 24, 25, 
 35     24, 25, 26, 27, 28, 29, 
 36     28, 29, 30, 31, 32, 1 
 37 }; 
 38 
 39 const int p32i[] = { 
 40     16, 7, 20, 21, 
 41     29, 12, 28, 17, 
 42     1, 15, 23, 26, 
 43     5, 18, 31, 10, 
 44     2, 8, 24, 14, 
 45     32, 27, 3, 9, 
 46     19, 13, 30, 6, 
 47     22, 11, 4, 25 
 48 }; 
 49 
 50 const int sbox[8][64] = { 
 51     /* S1 */ 
 52     14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7, 
 53     0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8, 
 54     4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0, 
 55     15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13, 
 56     /* S2 */ 
 57     15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10, 
 58     3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5, 
 59     0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15, 
 60     13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9, 
 61     /* S3 */ 
 62     10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8, 
 63     13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1, 
 64     13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7, 
 65     1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12, 
 66     /* S4 */ 
 67     7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15, 
 68     13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9, 
 69     10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4, 
 70     3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14, 
 71     /* S5 */ 
 72     2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9, 
 73     14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6, 
 74     4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14, 
 75     11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3, 
 76     /* S6 */ 
 77     12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11, 
 78     10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8, 
 79     9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6, 
 80     4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13, 
 81     /* S7 */ 
 82     4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1, 
 83     13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6, 
 84     1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2, 
 85     6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12, 
 86     /* S8 */ 
 87     13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7, 
 88     1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2, 
 89     7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8, 
 90     2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11 
 91 }; 
 92 
 93 const int pc1[] = { 
 94     57, 49, 41, 33, 25, 17, 9, 
 95     1, 58, 50, 42, 34, 26, 18, 
 96     10, 2, 59, 51, 43, 35, 27, 
 97     19, 11, 3, 60, 52, 44, 36, 
 98     63, 55, 47, 39, 31, 23, 15, 
 99     7, 62, 54, 46, 38, 30, 22, 
100     14, 6, 61, 53, 45, 37, 29, 
101     21, 13, 5, 28, 20, 12, 4 
102 }; 
103 
104 const int pc2[] = { 
105     14, 17, 11, 24, 1, 5, 
106     3, 28, 15, 6, 21, 10, 
107     23, 19, 12, 4, 26, 8, 
108     16, 7, 27, 20, 13, 2, 
109     41, 52, 31, 37, 47, 55, 
110     30, 40, 51, 45, 33, 48, 
111     44, 49, 39, 56, 34, 53, 
112     46, 42, 50, 36, 29, 32 
113 }; 
114 
115 
116 /* number left rotations of pc1 */ 
117 const int totrot[] = { 
118     1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
119 }; 
120 
121 //循环左移
122 inline void circleLeftMove(std::bitset<28> &bit28)
123 {
124     int temp = bit28[27];
125     bit28 <<= 1;
126     bit28 |= temp;
127 }
128 
129 //初始置换
130 inline void initialExchange(std::bitset<64> &bit64, std::bitset<32> &L, std::bitset<32> &R)
131 {
132     for (int i = 0; i < 64; i++)
133     {
134         if (i >= 32)
135             R.set(63 - i, bit64[64 - ip[i]]);
136         else
137             L.set(31 - i, bit64[64 - ip[i]]);
138     }
139 }
140 
141 //逆初始置换
142 inline void uninitialExchange(std::bitset<64> &bit64, std::bitset<32> &L, std::bitset<32> &R)
143 {
144     for (int i = 0; i < 64; i++)
145     {
146         int index = fp[i];
147         if (index > 32)
148             bit64.set(63 - i, L[64 - fp[i]]);
149             //R.set(63 - i, bit64[63 - ip[i]]);
150         else
151             bit64.set(63 - i, R[32 - fp[i]]);
152             //L.set(31 - i, bit64[63 - ip[i]]);
153     }
154 }
155 
156 //扩充置换
157 inline std::bitset<48> expandExchange(std::bitset<32> &bit32)
158 {
159     std::bitset<48> retBit48(0);
160     for (int i = 0; i < 48; i++)
161         retBit48.set(47 - i, bit32[32 - ei[i]]);
162     return retBit48;
163 }
164 
165 //置换选择1
166 inline void exchangeChoose(std::bitset<64> &bit64, std::bitset<28> &C, std::bitset<28> &D)
167 {
168     for (int i = 0; i < 56; i++)
169     {
170         if (i >= 28)
171             D.set(55 - i, bit64[64 - pc1[i]]);
172         else
173             C.set(27 - i, bit64[64 - pc1[i]]);
174     }
175 }
176 
177 //置换选择2
178 inline std::bitset<48> exchangeChoose(std::bitset<28> &C, std::bitset<28> &D)
179 {
180     std::bitset<48> retBit48(0);
181     int index;
182     for (int i = 0; i < 48; i++)
183     {
184         index = pc2[i];
185         if (index > 28)
186             retBit48.set(47 - i, D[56 - index]);
187         else
188             retBit48.set(47 - i, C[28 - index]);
189     }
190     return retBit48;
191 }
192 
193 //代换选择（S盒）
194 inline std::bitset<32> replaceChoose(std::bitset<48> &bit48)
195 {
196     std::bitset<32> retBit32(0);
197     std::bitset<6> temp(0);
198     int row, col;
199     for (int i = 0; i < 8; i++)
200     {
201         for (int j = 0; j < 6; j++)
202             temp.set(j, bit48[(7 - i) * 6 + j]);
203         row = temp[5] * 2 + temp[0];
204         temp <<= 1;
205         temp >>= 2;
206         col = (int)temp.to_ulong();
207         retBit32 <<= 4;
208         retBit32 |= sbox[i][row * 16 + col];
209     }
210     return retBit32;
211 }
212 
213 //置换
214 inline std::bitset<32> exchange(std::bitset<32> &bit32)
215 {
216     std::bitset<32> retBit32(0);
217     for (int i = 0; i < 32; i++)
218         retBit32.set(31 - i, bit32[32 - p32i[i]]);
219     return retBit32;
220 }
221 
222 //一次迭代
223 inline void onceIteration(std::bitset<32> &L, std::bitset<32> &R, std::bitset<28> &C, std::bitset<28> &D, int index)
224 {
225     for (int i = 0; i < totrot[index]; i++)
226     {
227         circleLeftMove(C);
228         circleLeftMove(D);
229     }
230     L ^= exchange(replaceChoose(expandExchange(R) ^ exchangeChoose(C, D)));
231     std::bitset<32> temp = R;
232 
233     R = L;
234     L = temp;
235 }
236 
237 inline void encypher(std::bitset<64> &text, std::bitset<64> &cipherKey)
238 {
239     std::bitset<28> C = 0, D = 0;
240     std::bitset<32> L = 0, R = 0;
241     exchangeChoose(cipherKey, C, D);
242     initialExchange(text, L, R);
243     for (int i = 0; i < 16; i++)
244         onceIteration(L, R, C, D, i);
245     uninitialExchange(text, L, R);
246 }

1 //main.cpp
 2 #include <iostream>
 3 #include "des.h"
 4 #include <cstring>
 5 using namespace std;
 6 
 7 int main(int argc, char **argv)
 8 {
 9     char cipherKeyStr[65];
10     char textStr[65];
11     cout << "please input the cipher key:";
12     cin >> cipherKeyStr;
13     cout << "please input the plaintext:";
14     cin >> textStr;
15     bitset<64> cipherKey(cipherKeyStr);
16     bitset<64> text(textStr);
17     encypher(text, cipherKey);
18     cout << text << endl;
19 }

可以用http://hi.baidu.com/barrypp/item/d7983d19b9e02d426826bbe7里的数据来测试。注意把16进制数转换成2进制数

另外注意一下C++中inline的使用，如果你用了inline，你想运行修改后的代码，必须要把整个工程重新编译生成代码才能成功。好吧，到今天才发现这个问题，真的是太水了，各路大神勿喷==
原文链接: https://www.cnblogs.com/MichaelChong/archive/2013/04/12/3017228.html

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