/********************************************************************* * Filename: des.cpp * Author: Brad Conte (brad AT radconte.com) * Copyright: * Disclaimer: This code is presented "as is" without any guarantees. * Details: Implementation of the DES encryption algorithm. Modes of operation (such as CBC) are not included. The formal NIST algorithm specification can be found here: * http://csrc.nist.gov/publications/fips/fips46-3/fips46-3.pdf *********************************************************************/ /*************************** HEADER FILES ***************************/ #include #include #include "des.h" /****************************** MACROS ******************************/ // Obtain bit "b" from the left and shift it "c" places from the right #define BITNUM(a, b, c) (((a[(b) / 32 * 4 + 3 - (b) % 32 / 8] >> (7 - (b % 8))) & 0x01) << (c)) #define BITNUMINTR(a, b, c) ((((a) >> (31 - (b))) & 0x00000001) << (c)) #define BITNUMINTL(a, b, c) ((((a) << (b)) & 0x80000000) >> (c)) // This macro converts a 6 bit block with the S-Box row defined as the first and last // bits to a 6 bit block with the row defined by the first two bits. #define SBOXBIT(a) (((a)&0x20) | (((a)&0x1f) >> 1) | (((a)&0x01) << 4)) /**************************** VARIABLES *****************************/ static const BYTE sbox1[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}; static const BYTE sbox2[64] = { 15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10, 3, 13, 4, 7, 15, 2, 8, 15, 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}; static const BYTE sbox3[64] = { 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}; static const BYTE sbox4[64] = { 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, 10, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14}; static const BYTE sbox5[64] = { 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}; static const BYTE sbox6[64] = { 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}; static const BYTE sbox7[64] = { 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}; static const BYTE sbox8[64] = { 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}; /*********************** FUNCTION DEFINITIONS ***********************/ // Initial (Inv)Permutation step void IP(WORD state[], const BYTE in[]) { state[0] = BITNUM(in, 57, 31) | BITNUM(in, 49, 30) | BITNUM(in, 41, 29) | BITNUM(in, 33, 28) | BITNUM(in, 25, 27) | BITNUM(in, 17, 26) | BITNUM(in, 9, 25) | BITNUM(in, 1, 24) | BITNUM(in, 59, 23) | BITNUM(in, 51, 22) | BITNUM(in, 43, 21) | BITNUM(in, 35, 20) | BITNUM(in, 27, 19) | BITNUM(in, 19, 18) | BITNUM(in, 11, 17) | BITNUM(in, 3, 16) | BITNUM(in, 61, 15) | BITNUM(in, 53, 14) | BITNUM(in, 45, 13) | BITNUM(in, 37, 12) | BITNUM(in, 29, 11) | BITNUM(in, 21, 10) | BITNUM(in, 13, 9) | BITNUM(in, 5, 8) | BITNUM(in, 63, 7) | BITNUM(in, 55, 6) | BITNUM(in, 47, 5) | BITNUM(in, 39, 4) | BITNUM(in, 31, 3) | BITNUM(in, 23, 2) | BITNUM(in, 15, 1) | BITNUM(in, 7, 0); state[1] = BITNUM(in, 56, 31) | BITNUM(in, 48, 30) | BITNUM(in, 40, 29) | BITNUM(in, 32, 28) | BITNUM(in, 24, 27) | BITNUM(in, 16, 26) | BITNUM(in, 8, 25) | BITNUM(in, 0, 24) | BITNUM(in, 58, 23) | BITNUM(in, 50, 22) | BITNUM(in, 42, 21) | BITNUM(in, 34, 20) | BITNUM(in, 26, 19) | BITNUM(in, 18, 18) | BITNUM(in, 10, 17) | BITNUM(in, 2, 16) | BITNUM(in, 60, 15) | BITNUM(in, 52, 14) | BITNUM(in, 44, 13) | BITNUM(in, 36, 12) | BITNUM(in, 28, 11) | BITNUM(in, 20, 10) | BITNUM(in, 12, 9) | BITNUM(in, 4, 8) | BITNUM(in, 62, 7) | BITNUM(in, 54, 6) | BITNUM(in, 46, 5) | BITNUM(in, 38, 4) | BITNUM(in, 30, 3) | BITNUM(in, 22, 2) | BITNUM(in, 14, 1) | BITNUM(in, 6, 0); } void InvIP(WORD state[], BYTE in[]) { in[3] = BITNUMINTR(state[1], 7, 7) | BITNUMINTR(state[0], 7, 6) | BITNUMINTR(state[1], 15, 5) | BITNUMINTR(state[0], 15, 4) | BITNUMINTR(state[1], 23, 3) | BITNUMINTR(state[0], 23, 2) | BITNUMINTR(state[1], 31, 1) | BITNUMINTR(state[0], 31, 0); in[2] = BITNUMINTR(state[1], 6, 7) | BITNUMINTR(state[0], 6, 6) | BITNUMINTR(state[1], 14, 5) | BITNUMINTR(state[0], 14, 4) | BITNUMINTR(state[1], 22, 3) | BITNUMINTR(state[0], 22, 2) | BITNUMINTR(state[1], 30, 1) | BITNUMINTR(state[0], 30, 0); in[1] = BITNUMINTR(state[1], 5, 7) | BITNUMINTR(state[0], 5, 6) | BITNUMINTR(state[1], 13, 5) | BITNUMINTR(state[0], 13, 4) | BITNUMINTR(state[1], 21, 3) | BITNUMINTR(state[0], 21, 2) | BITNUMINTR(state[1], 29, 1) | BITNUMINTR(state[0], 29, 0); in[0] = BITNUMINTR(state[1], 4, 7) | BITNUMINTR(state[0], 4, 6) | BITNUMINTR(state[1], 12, 5) | BITNUMINTR(state[0], 12, 4) | BITNUMINTR(state[1], 20, 3) | BITNUMINTR(state[0], 20, 2) | BITNUMINTR(state[1], 28, 1) | BITNUMINTR(state[0], 28, 0); in[7] = BITNUMINTR(state[1], 3, 7) | BITNUMINTR(state[0], 3, 6) | BITNUMINTR(state[1], 11, 5) | BITNUMINTR(state[0], 11, 4) | BITNUMINTR(state[1], 19, 3) | BITNUMINTR(state[0], 19, 2) | BITNUMINTR(state[1], 27, 1) | BITNUMINTR(state[0], 27, 0); in[6] = BITNUMINTR(state[1], 2, 7) | BITNUMINTR(state[0], 2, 6) | BITNUMINTR(state[1], 10, 5) | BITNUMINTR(state[0], 10, 4) | BITNUMINTR(state[1], 18, 3) | BITNUMINTR(state[0], 18, 2) | BITNUMINTR(state[1], 26, 1) | BITNUMINTR(state[0], 26, 0); in[5] = BITNUMINTR(state[1], 1, 7) | BITNUMINTR(state[0], 1, 6) | BITNUMINTR(state[1], 9, 5) | BITNUMINTR(state[0], 9, 4) | BITNUMINTR(state[1], 17, 3) | BITNUMINTR(state[0], 17, 2) | BITNUMINTR(state[1], 25, 1) | BITNUMINTR(state[0], 25, 0); in[4] = BITNUMINTR(state[1], 0, 7) | BITNUMINTR(state[0], 0, 6) | BITNUMINTR(state[1], 8, 5) | BITNUMINTR(state[0], 8, 4) | BITNUMINTR(state[1], 16, 3) | BITNUMINTR(state[0], 16, 2) | BITNUMINTR(state[1], 24, 1) | BITNUMINTR(state[0], 24, 0); } WORD f(WORD state, const BYTE key[]) { BYTE lrgstate[6]; //,i; WORD t1, t2; // Expantion Permutation t1 = BITNUMINTL(state, 31, 0) | ((state & 0xf0000000) >> 1) | BITNUMINTL(state, 4, 5) | BITNUMINTL(state, 3, 6) | ((state & 0x0f000000) >> 3) | BITNUMINTL(state, 8, 11) | BITNUMINTL(state, 7, 12) | ((state & 0x00f00000) >> 5) | BITNUMINTL(state, 12, 17) | BITNUMINTL(state, 11, 18) | ((state & 0x000f0000) >> 7) | BITNUMINTL(state, 16, 23); t2 = BITNUMINTL(state, 15, 0) | ((state & 0x0000f000) << 15) | BITNUMINTL(state, 20, 5) | BITNUMINTL(state, 19, 6) | ((state & 0x00000f00) << 13) | BITNUMINTL(state, 24, 11) | BITNUMINTL(state, 23, 12) | ((state & 0x000000f0) << 11) | BITNUMINTL(state, 28, 17) | BITNUMINTL(state, 27, 18) | ((state & 0x0000000f) << 9) | BITNUMINTL(state, 0, 23); lrgstate[0] = (t1 >> 24) & 0x000000ff; lrgstate[1] = (t1 >> 16) & 0x000000ff; lrgstate[2] = (t1 >> 8) & 0x000000ff; lrgstate[3] = (t2 >> 24) & 0x000000ff; lrgstate[4] = (t2 >> 16) & 0x000000ff; lrgstate[5] = (t2 >> 8) & 0x000000ff; // Key XOR lrgstate[0] ^= key[0]; lrgstate[1] ^= key[1]; lrgstate[2] ^= key[2]; lrgstate[3] ^= key[3]; lrgstate[4] ^= key[4]; lrgstate[5] ^= key[5]; // S-Box Permutation state = (sbox1[SBOXBIT(lrgstate[0] >> 2)] << 28) | (sbox2[SBOXBIT(((lrgstate[0] & 0x03) << 4) | (lrgstate[1] >> 4))] << 24) | (sbox3[SBOXBIT(((lrgstate[1] & 0x0f) << 2) | (lrgstate[2] >> 6))] << 20) | (sbox4[SBOXBIT(lrgstate[2] & 0x3f)] << 16) | (sbox5[SBOXBIT(lrgstate[3] >> 2)] << 12) | (sbox6[SBOXBIT(((lrgstate[3] & 0x03) << 4) | (lrgstate[4] >> 4))] << 8) | (sbox7[SBOXBIT(((lrgstate[4] & 0x0f) << 2) | (lrgstate[5] >> 6))] << 4) | sbox8[SBOXBIT(lrgstate[5] & 0x3f)]; // P-Box Permutation state = BITNUMINTL(state, 15, 0) | BITNUMINTL(state, 6, 1) | BITNUMINTL(state, 19, 2) | BITNUMINTL(state, 20, 3) | BITNUMINTL(state, 28, 4) | BITNUMINTL(state, 11, 5) | BITNUMINTL(state, 27, 6) | BITNUMINTL(state, 16, 7) | BITNUMINTL(state, 0, 8) | BITNUMINTL(state, 14, 9) | BITNUMINTL(state, 22, 10) | BITNUMINTL(state, 25, 11) | BITNUMINTL(state, 4, 12) | BITNUMINTL(state, 17, 13) | BITNUMINTL(state, 30, 14) | BITNUMINTL(state, 9, 15) | BITNUMINTL(state, 1, 16) | BITNUMINTL(state, 7, 17) | BITNUMINTL(state, 23, 18) | BITNUMINTL(state, 13, 19) | BITNUMINTL(state, 31, 20) | BITNUMINTL(state, 26, 21) | BITNUMINTL(state, 2, 22) | BITNUMINTL(state, 8, 23) | BITNUMINTL(state, 18, 24) | BITNUMINTL(state, 12, 25) | BITNUMINTL(state, 29, 26) | BITNUMINTL(state, 5, 27) | BITNUMINTL(state, 21, 28) | BITNUMINTL(state, 10, 29) | BITNUMINTL(state, 3, 30) | BITNUMINTL(state, 24, 31); // Return the final state value return (state); } void des_key_setup(const BYTE key[], BYTE schedule[][6], DES_MODE mode) { WORD i, j, to_gen, C, D; const WORD key_rnd_shift[16] = {1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1}; const WORD key_perm_c[28] = {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}; const WORD key_perm_d[28] = {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 WORD key_compression[48] = {13, 16, 10, 23, 0, 4, 2, 27, 14, 5, 20, 9, 22, 18, 11, 3, 25, 7, 15, 6, 26, 19, 12, 1, 40, 51, 30, 36, 46, 54, 29, 39, 50, 44, 32, 47, 43, 48, 38, 55, 33, 52, 45, 41, 49, 35, 28, 31}; // Permutated Choice #1 (copy the key in, ignoring parity bits). for (i = 0, j = 31, C = 0; i < 28; ++i, --j) C |= BITNUM(key, key_perm_c[i], j); for (i = 0, j = 31, D = 0; i < 28; ++i, --j) D |= BITNUM(key, key_perm_d[i], j); // Generate the 16 subkeys. for (i = 0; i < 16; ++i) { C = ((C << key_rnd_shift[i]) | (C >> (28 - key_rnd_shift[i]))) & 0xfffffff0; D = ((D << key_rnd_shift[i]) | (D >> (28 - key_rnd_shift[i]))) & 0xfffffff0; // Decryption subkeys are reverse order of encryption subkeys so // generate them in reverse if the key schedule is for decryption useage. if (mode == DES_DECRYPT) to_gen = 15 - i; else /*(if mode == DES_ENCRYPT)*/ to_gen = i; // Initialize the array for (j = 0; j < 6; ++j) schedule[to_gen][j] = 0; for (j = 0; j < 24; ++j) schedule[to_gen][j / 8] |= BITNUMINTR(C, key_compression[j], 7 - (j % 8)); for (; j < 48; ++j) schedule[to_gen][j / 8] |= BITNUMINTR(D, key_compression[j] - 27, 7 - (j % 8)); } } void des_crypt(const BYTE in[], BYTE out[], const BYTE key[][6]) { WORD state[2], idx, t; IP(state, in); for (idx = 0; idx < 15; ++idx) { t = state[1]; state[1] = f(state[1], key[idx]) ^ state[0]; state[0] = t; } // Perform the final loop manually as it doesn't switch sides state[0] = f(state[1], key[15]) ^ state[0]; InvIP(state, out); } /* void three_des_key_setup(const BYTE key[], BYTE schedule[][16][6], DES_MODE mode) { if (mode == DES_ENCRYPT) { des_key_setup(&key[0], schedule[0], mode); des_key_setup(&key[8], schedule[1], DES_DECRYPT); des_key_setup(&key[16], schedule[2], mode); } else // if (mode == DES_DECRYPT { des_key_setup(&key[16], schedule[0], mode); des_key_setup(&key[8], schedule[1], DES_ENCRYPT); des_key_setup(&key[0], schedule[2], mode); } } void three_des_crypt(const BYTE in[], BYTE out[], const BYTE key[][16][6]) { des_crypt(in, out, key[0]); des_crypt(out, out, key[1]); des_crypt(out, out, key[2]); } */