可用于单片机的DES加密算法
在写设计文档，突然被提起传输的数据最好还是加密！惶恐！你知道吗？单片机算DES，不是我疯掉就是单片机疯掉！
然后搜了下，感谢各位神仙~居然有这么多实现过的，下面是一例。
据说是已经测试通过的，最早为8位单片设计的，我也还没测，先找来放着，看着也心安。
//以下是des.c文件全部： //密钥： B4 31 5B 86 9D 7D FA A2 //数据： 1F AD 61 A5 F7 19 77 14 //DES加密结果：4C 78 E9 1A F2 DA 9C D3 const uint8_t initial_tr[64] = { 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, 56, 48, 40, 32, 24, 16, 8, 0, 58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6 }; const uint8_t final_tr[64] = { 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, 32, 0, 40, 8, 48, 16, 56, 24 }; const uint8_t swap[64] = { 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, 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 }; const uint8_t key_tr1[56] = { 56, 48, 40, 32, 24, 16, 8, 0, 57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51, 43, 35, 62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 60, 52, 44, 36, 28, 20, 12, 4, 27, 19, 11, 3 }; const uint8_t key_tr2[64] = { 0, 0, 13, 4, 16, 10, 23, 0, 0, 0, 2, 9, 27, 14, 5, 20, 0, 0, 22, 7, 18, 11, 3, 25, 0, 0, 15, 1, 6, 26, 19, 12, 0, 0, 40, 54, 51, 30, 36, 46, 0, 0, 29, 47, 39, 50, 44, 32, 0, 0, 43, 52, 48, 38, 55, 33, 0, 0, 45, 31, 41, 49, 35, 28 }; const uint8_t etr[64] = { 0, 0, 31, 4, 0, 1, 2, 3, 0, 0, 3, 8, 4, 5, 6, 7, 0, 0, 7, 12, 8, 9, 10, 11, 0, 0, 11, 16, 12, 13, 14, 15, 0, 0, 15, 20, 16, 17, 18, 19, 0, 0, 19, 24, 20, 21, 22, 23, 0, 0, 23, 28, 24, 25, 26, 27, 0, 0, 27, 0, 28, 29, 30, 31 }; const uint8_t ptr[32] = { 31, 14, 39, 44, 60, 23, 55, 36, 4, 30, 46, 53, 12, 37, 62, 21, 5, 15, 47, 29, 63, 54, 6, 20, 38, 28, 61, 13, 45, 22, 7, 52 }; const uint8_t s[8][64] = { { 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 } }; const uint8_t rots[16] = { 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 }; const uint8_t bit_msk[8] = { 0x80, 0x40, 0x20, 0x10, 0x08, 0x04, 0x02, 0x01 }; uint8_t DES_Encrypt_key[8]; uint8_t DES_Decrypt_key[8]; uint8_t sub_keys[16][8]; //sub_keys[16][8] uint8_t main_key[8]; void des(uint8_t*, uint8_t*, uint8_t, uint8_t*); void FLASH_Read_KEYS(uint8_t key_index); static void transpose (uint8_t*, uint8_t*, const uint8_t*, uint8_t); static void rotate_l (uint8_t*); static void compute_subkeys (uint8_t*); static void f (uint8_t*, uint8_t*, uint8_t*); /************************************************************************/ /* */ /* Module title: des */ /* Module type: des mainrutine */ /* */ /* Author: YXH */ /* Date: 2012-07-13 */ /* */ /* Last changed by: YXH */ /* Date: 2012-07-13 */ /* */ /* Functional Description: Encipher and decipher 64 bits string */ /* according to a 64 bits key string */ /* The string format is shown below */ /* */ /* input parameter 1: pointer to 64 bits input string */ /* 2: pointer to 64 bits key string */ /* 3: boolean if false indicating enciphering */ /* if true dechiphering */ /* 4: pointer to a 64 bits output string */ /************************************************************************/ /* */ /* msb lsb */ /* bit bit */ /* +-- -- -- -- -- -- -- --+ */ /* addr !1st 8th! */ /* +-- -- -- -- -- -- -- --+ */ /* addr+1 !9th 16th! */ /* +-- -- -- -- -- -- -- --+ */ /* : : */ /* : : */ /* +-- -- -- -- -- -- -- --+ */ /* addr+7 !57th 64th! */ /* +-- -- -- -- -- -- -- --+ */ /* */ /************************************************************************/ void des(uint8_t *plain_strng, uint8_t *key, uint8_t d, uint8_t *ciph_strng) { uint8_t a_str[8], b_str[8], x_str[8]; uint8_t i, j, *pkey, temp; for (i = 0; i < 8 ; ++i) { if (key[i] != main_key[i]) { compute_subkeys(key); i = 7; } } transpose(plain_strng, a_str, initial_tr, 64); for (i=1; i < 17; ++i) { for (j=0; j < 8; ++j){b_str[j] = a_str[j];} if (!d) /*enchipher*/ pkey = &sub_keys[i-1][0]; else /*dechipher*/ pkey = &sub_keys[16-i][0]; for (j=0; j < 4; ++j){a_str[j] = b_str[j+4];} f(pkey, a_str, x_str); for (j=0; j < 4; ++j) {a_str[j+4] = b_str[j] ^ x_str[j];} } temp = a_str[0]; a_str[0] = a_str[4]; a_str[4] = temp; temp = a_str[1]; a_str[1] = a_str[5]; a_str[5] = temp; temp = a_str[2]; a_str[2] = a_str[6]; a_str[6] = temp; temp = a_str[3]; a_str[3] = a_str[7]; a_str[7] = temp; transpose(a_str, ciph_strng, final_tr, 64); } /************************************************************************/ /* */ /* Module title: transpose */ /* Module type: des subrutine */ /* */ /* Author: YXH */ /* Date: 2012-07-13 */ /* */ /* Last changed by: YXH */ /* Date: 2012-07-13 */ /* */ /* Functional Description: Permute n bits in a string, according */ /* to a table describing the new order. */ /* 0 < n <= 64 */ /* */ /* input parameter 1: pointer to first byte in input string */ /* 2: pointer to first byte in output string */ /* 3: pointer to table describing new order */ /* 4: number of bits to be permuted */ /************************************************************************/ void transpose(uint8_t *idata, uint8_t *odata, const uint8_t *tbl, uint8_t n) { const uint8_t *tab_adr; int i, bi_idx; tab_adr = &bit_msk[0]; i = 0; do {odata[i++] = 0;} while (i < 8); i = 0; do { bi_idx = *tbl++; if (idata[bi_idx>>3] & tab_adr[bi_idx & 7]) { odata[i>>3] |= tab_adr[i & 7]; } } while (++i < n); } /************************************************************************/ /* */ /* Module title: rotate_l */ /* Module type: des subrutine */ /* */ /* Author: YXH */ /* Date: 2012-07-13 */ /* */ /* Last changed by: YXH */ /* Date: 2012-07-13 */ /* */ /* Functional Description: rotate 2 concatenated strings of 28 */ /* bits one position to the left. */ /* */ /* input parameter 1: pointer to first byte in key string */ /* */ /************************************************************************/ void rotate_l(uint8_t *key) { uint8_t str_x[8]; uint8_t i; for (i=0; i < 8; ++i) str_x[i] = key[i]; for (i=0; i < 7; ++i) { key[i] = (key[i] << 1); if ((i < 6) && ((str_x[i+1] & 128) == 128)) key[i] |= 1; } if (str_x[0] & 0x80 ) key[3] |= 0x10; else key[3] &= ~0x10; if (str_x[3] & 0x08 ) key[6] |= 0x01; else key[6] &= ~0x01; } /************************************************************************/ /* */ /* Module title: compute_subkeys */ /* Module type: des subrutine */ /* */ /* Author: YXH */ /* Date: 2012-07-13 */ /* */ /* Last changed by: YXH */ /* Date: 2012-07-13 */ /* */ /* Functional Description: Computes the 16 sub keys for use in the */ /* DES algorithm */ /* */ /* input parameter 1: pointer to first byte in key string */ /* output : fills the array sub_keys[16][8] with */ /* sub keys and stores the input key in */ /* main_key[8] */ /************************************************************************/ void compute_subkeys(uint8_t *key) { uint8_t i, j, ikey[8], okey[8]; for (i=0; i < 8; ++i) { main_key[i] = key[i]; } transpose(key, ikey, key_tr1, 56); for (i=0; i < 16; ++i) { for (j=0; j < rots[i]; ++j) {rotate_l(ikey);} transpose(ikey, okey, key_tr2, 64); for (j=0; j < 8; ++j) { sub_keys[i][j] = okey[j];} } } /************************************************************************/ /* */ /* Module title: f */ /* Module type: des subrutine */ /* */ /* Author: YXH */ /* Date: 2012-07-13 */ /* */ /* Last changed by: YXH */ /* Date: 2012-07-13 */ /* */ /* Functional Description: The chipher function */ /* */ /* input parameter 1: pointer to first byte in key string */ /* 2: pointer to a 32 bit input string */ /* 3: pointer to a 32 bit output string */ /************************************************************************/ void f(uint8_t *skey, uint8_t *a_str, uint8_t *x_str) { uint8_t e_str[8], y_str[8], z_str[8]; uint8_t k; transpose(a_str, e_str, etr, 64); for (k=0; k < 8; ++k) { y_str[k] = (e_str[k] ^ skey[k]) & 63; z_str[k] = s[k] [y_str[k]]; } transpose(z_str, x_str, ptr, 32); }
还是要感谢作者的无私奉献的：http://www.eefocus.com/yuanxihua/blog/12-09/285439_1e3bb.html