Advertisement
Not a member of Pastebin yet?
Sign Up,
it unlocks many cool features!
- #include <iostream>
- #include <fstream>
- #include <bitset>
- #include <string>
- using namespace std;
- bitset<64> key; // 64位密钥
- bitset<48> subKey[16]; // 存放16轮子密钥
- // 初始置换表
- int 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};
- // 结尾置换表
- int 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};
- /*------------------下面是生成密钥所用表-----------------*/
- // 密钥置换表,将64位密钥变成56位
- int PC_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};
- // 压缩置换,将56位密钥压缩成48位子密钥
- int PC_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};
- // 每轮左移的位数
- int shiftBits[] = {1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1};
- /*------------------下面是密码函数 f 所用表-----------------*/
- // 扩展置换表,将 32位 扩展至 48位
- int 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};
- // S盒,每个S盒是4x16的置换表,6位 -> 4位
- int S_BOX[8][4][16] = {
- {
- {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置换,32位 -> 32位
- int 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 };
- /**********************************************************************/
- /* */
- /* 下面是DES算法实现 */
- /* */
- /**********************************************************************/
- /**
- * 密码函数f,接收32位数据和48位子密钥,产生一个32位的输出
- */
- bitset<32> f(bitset<32> R, bitset<48> k)
- {
- bitset<48> expandR;
- // 第一步:扩展置换,32 -> 48
- for(int i=0; i<48; ++i)
- expandR[47-i] = R[32-E[i]];
- // 第二步:异或
- expandR = expandR ^ k;
- // 第三步:查找S_BOX置换表
- bitset<32> output;
- int x = 0;
- for(int i=0; i<48; i=i+6)
- {
- int row = expandR[47-i]*2 + expandR[47-i-5];
- int col = expandR[47-i-1]*8 + expandR[47-i-2]*4 + expandR[47-i-3]*2 + expandR[47-i-4];
- int num = S_BOX[i/6][row][col];
- bitset<4> binary(num);
- output[31-x] = binary[3];
- output[31-x-1] = binary[2];
- output[31-x-2] = binary[1];
- output[31-x-3] = binary[0];
- x += 4;
- }
- // 第四步:P-置换,32 -> 32
- bitset<32> tmp = output;
- for(int i=0; i<32; ++i)
- output[31-i] = tmp[32-P[i]];
- return output;
- }
- /**
- * 对56位密钥的前后部分进行左移
- */
- bitset<28> leftShift(bitset<28> k, int shift)
- {
- bitset<28> tmp = k;
- for(int i=27; i>=0; --i)
- {
- if(i-shift<0)
- k[i] = tmp[i-shift+28];
- else
- k[i] = tmp[i-shift];
- }
- return k;
- }
- /**
- * 生成16个48位的子密钥
- */
- void generateKeys()
- {
- bitset<56> realKey;
- bitset<28> left;
- bitset<28> right;
- bitset<48> compressKey;
- // 去掉奇偶标记位,将64位密钥变成56位
- for (int i=0; i<56; ++i)
- realKey[55-i] = key[64 - PC_1[i]];
- // 生成子密钥,保存在 subKeys[16] 中
- for(int round=0; round<16; ++round)
- {
- // 前28位与后28位
- for(int i=28; i<56; ++i)
- left[i-28] = realKey[i];
- for(int i=0; i<28; ++i)
- right[i] = realKey[i];
- // 左移
- left = leftShift(left, shiftBits[round]);
- right = leftShift(right, shiftBits[round]);
- // 压缩置换,由56位得到48位子密钥
- for(int i=28; i<56; ++i)
- realKey[i] = left[i-28];
- for(int i=0; i<28; ++i)
- realKey[i] = right[i];
- for(int i=0; i<48; ++i)
- compressKey[47-i] = realKey[56 - PC_2[i]];
- subKey[round] = compressKey;
- }
- }
- /**
- * 工具函数:将char字符数组转为二进制
- */
- bitset<64> charToBitset(const char s[8])
- {
- bitset<64> bits;
- for(int i=0; i<8; ++i)
- for(int j=0; j<8; ++j)
- bits[i*8+j] = ((s[i]>>j) & 1);
- return bits;
- }
- template<size_t len>
- string Bitset2String(const bitset<len> & bits)
- {
- if(len%8)
- return "";
- string s;
- for(int i=0;i<64/8;++i){
- char var=0;
- for(int j=0;j<8;++j){
- var=var|(bits[i*8+j]<<j);
- }
- s.push_back(var);
- }
- return s;
- }
- /*
- * flag 为真为加密,为假为解密
- */
- bitset<64> des(bitset<64>& cipher,bool flag)
- {
- bitset<64> plain;
- bitset<64> currentBits;
- bitset<32> left;
- bitset<32> right;
- bitset<32> newLeft;
- // 第一步:初始置换IP
- for(int i=0; i<64; ++i)
- currentBits[63-i] = cipher[64-IP[i]];
- // 第二步:获取 Li 和 Ri
- for(int i=32; i<64; ++i)
- left[i-32] = currentBits[i];
- for(int i=0; i<32; ++i)
- right[i] = currentBits[i];
- // 第三步:共16轮迭代
- for(int round=0; round<16; ++round)
- {
- newLeft = right;
- right = left ^ f(right,flag?subKey[round]:subKey[15-round]);
- left = newLeft;
- }
- // 第四步:合并L16和R16,注意合并为 R16L16
- for(int i=0; i<32; ++i)
- plain[i] = left[i];
- for(int i=32; i<64; ++i)
- plain[i] = right[i-32];
- // 第五步:结尾置换IP-1
- currentBits = plain;
- for(int i=0; i<64; ++i)
- plain[63-i] = currentBits[64-IP_1[i]];
- // 返回明文
- return plain;
- }
- int main()
- {
- string s = "romantic";
- string k = "12345678";
- bitset<64> plain = charToBitset(s.c_str());
- key = charToBitset(k.c_str());
- // 生成16个子密钥
- generateKeys();
- //加密
- bitset<64> cipher = des(plain,true);
- string my=Bitset2String(cipher);
- cout<<my<<endl;
- //解密
- bitset<64> temp_plain = des(cipher,false);
- string my_plain=Bitset2String(temp_plain);
- cout<<my_plain<<endl;
- return 0;
- }
Advertisement
Add Comment
Please, Sign In to add comment
Advertisement