des算法的C语言实现

#include "des.h" #include "bitvec.h" #include <string.h> static unsigned 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 }; static unsigned int Shift_Array[] = { 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 }; static unsigned 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, }; static unsigned 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, }; static unsigned 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, }; static char S[][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, }; static unsigned 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, }; static unsigned int FP[] = { 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, }; struct des_t { BitVec<48> subkey[16]; }; static void des_transform_s(BitVec<48> & bv48) { BitVec<6> bv6; for (int i = 0; i < 8; i++) { BitCopy(bv6, bv48, i*6, 6, 0); char index1 = 0, index2 = 0; index1 |= bv6.GetBit(0) ? 0x1 : 0x0; index1 |= bv6.GetBit(5) ? 0x2 : 0x0; index2 |= bv6.GetBit(1) ? 0x1 : 0x0; index2 |= bv6.GetBit(2) ? 0x2 : 0x0; index2 |= bv6.GetBit(3) ? 0x4 : 0x0; index2 |= bv6.GetBit(4) ? 0x8 : 0x0; bv6.SetBits(&S[i][index1][index2], 6); BitCopy(bv48, bv6, 0, 6, i*6); } } static void des_encrypt_block(struct des_t *des, BitVec<64> &block64, bool encrypt) { BitVec<64> block64_perm; BitVec<32> block32_l, block32_r, p32, temp32; BitVec<48> block48_l, block48_r; BitPermutate(block64_perm, block64, IP, sizeof(IP)/sizeof(IP[0])); BitCopy(block32_l, block64_perm, 0, 32, 0); BitCopy(block32_r, block64_perm, 32, 32, 0); for (int i = 0; i < 16; i++) { BitPermutate(block48_r, block32_r, E, sizeof(E)/sizeof(E[0])); if (encrypt) BitXOR(block48_r, block48_r, des->subkey[i]); else BitXOR(block48_r, block48_r, des->subkey[15-i]); des_transform_s(block48_r); BitPermutate(p32, block48_r, P, sizeof(P)/sizeof(P[0])); BitCopy(temp32, block32_r, 0, 32, 0); BitXOR(block32_r, p32, block32_l); BitCopy(block32_l, temp32, 0, 32, 0); } BitCopy(block64_perm, block32_r, 0, 32, 0); BitCopy(block64_perm, block32_l, 0, 32, 32); BitPermutate(block64, block64_perm, FP, sizeof(FP)/sizeof(FP[0])); } struct des_t* des_alloc() { return new des_t(); } void des_free(struct des_t *des) { delete des; } void des_set_key(struct des_t *des, char *key, unsigned int key_len) { char dupkey[8] = {0}; if (key_len < 8) { memcpy(dupkey, key, key_len); } else { memcpy(dupkey, key, 8); } BitVec<64> keyvec64(dupkey, 64); BitVec<56> keyvec56; BitVec<28> subkey[2]; BitPermutate(keyvec56, keyvec64, PC_1, sizeof(PC_1)/sizeof(PC_1[0])); BitCopy(subkey[0], keyvec56, 0, 28, 0); BitCopy(subkey[1], keyvec56, 28, 28, 0); for (int i = 0; i < 16; i++) { for (int j = 0; j < 2; j++) subkey[j].RotateLeft(Shift_Array[i]); BitConcat(keyvec56, subkey, 2); BitPermutate(des->subkey[i], keyvec56, PC_2, sizeof(PC_2)/sizeof(PC_2[0])); } } void des_encrypt(struct des_t *des, const char *plain, unsigned int plain_len) { BitVec<64> block64; for (; plain_len>=8; plain_len-=8, plain+=8) { block64.SetBits(plain, 64); des_encrypt_block(des, block64, true); block64.DumpHex(); //des_encrypt_block(des, block64, false); //block64.DumpStr(); } if (plain_len > 0) { assert(plain_len < 8); block64.SetBits(plain, plain_len*8); des_encrypt_block(des, block64, true); block64.DumpHex(); //des_encrypt_block(des, block64, false); //block64.DumpStr(); } } void des_decrypt(struct des_t *des, const char *encrypt, unsigned int encrypt_len) { }