/* * TweAES-128 * * TweAES-128 is a minor extension of AES-128 [1], the NIST recommended * block cipher (based on the Rijndael cipher by Rijmen and Daemen * [2,3]), in that it accepts a very short tweak of size 1 nibble. * * 1. https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.197.pdf * 2. https://web.archive.org/web/20070203204845/https://csrc.nist.gov/ * CryptoToolkit/aes/rijndael/Rijndael.pdf * 3. https://link.springer.com/book/10.1007%2F978-3-662-04722-4 * */ #include "estate.h" /* * No. of bits in the expanded tweak * */ #define CRYPTO_EXPTWEAKBITS (8) /* * No. of rounds between tweak injection * i.e. tweak is added at intervals of * "CRYPTO_TWEAKING_PERIOD" starting at * round "CRYPTO_TWEAKING_PERIOD". */ #define CRYPTO_TWEAKING_PERIOD (2) /* * Multiplication by 2 in GF(8) with respect to the primitive polynomial * x^8 + x^4 + x^3 + x + 1 */ #define _FIELD_MULT_BY_2_IN_GF8(a) ((a&0x80) ? ((a<<1)^0x1b) : (a<<1)) /* * Sbox and its inverse */ const u8 _aes_sbox[256] = { 0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16 }; const u8 _aes_sbox_inv[256] = { 0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d }; /* * round constants */ const u8 _aes_round_constants[10] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36}; /********************************************************************** * * @name : bytes_to_bits * * @note : Convert byte oriented "src" to bit oriented "dest". * **********************************************************************/ void bytes_to_bits(u8 *dest, const u8 *src, u8 src_len) { for(u8 i=0; i> j) & 0x1; } } } /********************************************************************** * * @name : expand_tweak * * @note : Expand the 4-bit tweak input in "twk" into a * CRYPTO_EXPTWEAKBITS-bit expanded tweak in * "exp_twk". * **********************************************************************/ void expand_tweak(u8 *exp_twk, const u8 *twk) { u8 twk_; u8 parity = 0x00; // expand tweak nibble to byte by // copying the nibble to another twk_ = (twk[0]<<4) ^ twk[0]; // compute parity for(u8 i=0; i<4; i++) { parity ^= ((twk[0]>>i) & 0x1); } if(parity) { // XOR parity to the second nibble. twk_ ^= 0xf0; } // convert expanded tweak to bits bytes_to_bits(&exp_twk[0], &twk_, 1); } /********************************************************************** * * @name : generate_round_keys * * @note : Generate and store the round key bytes using the * master key. * **********************************************************************/ void generate_round_keys(u8 (*round_keys)[16], const u8 *key) { u8 temp[4]; for (u8 i = 0; i < 16; i++) { round_keys[0][i] = key[i]; } for (u8 i = 0; i < CRYPTO_BC_NUM_ROUNDS; i++) { // Key bytes 3...0 temp[3] = _aes_sbox[round_keys[i][12]]; temp[0] = _aes_sbox[round_keys[i][13]]; temp[1] = _aes_sbox[round_keys[i][14]]; temp[2] = _aes_sbox[round_keys[i][15]]; temp[0] ^= _aes_round_constants[i]; round_keys[i+1][0] = temp[0] ^ round_keys[i][0]; round_keys[i+1][1] = temp[1] ^ round_keys[i][1]; round_keys[i+1][2] = temp[2] ^ round_keys[i][2]; round_keys[i+1][3] = temp[3] ^ round_keys[i][3]; // Key bytes 7...4 round_keys[i+1][4] = round_keys[i+1][0] ^ round_keys[i][4]; round_keys[i+1][5] = round_keys[i+1][1] ^ round_keys[i][5]; round_keys[i+1][6] = round_keys[i+1][2] ^ round_keys[i][6]; round_keys[i+1][7] = round_keys[i+1][3] ^ round_keys[i][7]; // Key bytes 11...8 round_keys[i+1][8] = round_keys[i+1][4] ^ round_keys[i][8]; round_keys[i+1][9] = round_keys[i+1][5] ^ round_keys[i][9]; round_keys[i+1][10] = round_keys[i+1][6] ^ round_keys[i][10]; round_keys[i+1][11] = round_keys[i+1][7] ^ round_keys[i][11]; // Key bytes 15...12 round_keys[i+1][12] = round_keys[i+1][8] ^ round_keys[i][12]; round_keys[i+1][13] = round_keys[i+1][9] ^ round_keys[i][13]; round_keys[i+1][14] = round_keys[i+1][10] ^ round_keys[i][14]; round_keys[i+1][15] = round_keys[i+1][11] ^ round_keys[i][15]; } } /********************************************************************** * * @name : sub_bytes * * @note : SubBytes operation. * **********************************************************************/ void sub_bytes(u8 *state_bytes) { for (u8 i=0; i<16; i++) { state_bytes[i] = _aes_sbox[state_bytes[i]]; } } /********************************************************************** * * @name : sub_bytes_inv * * @note : Inverse SubBytes operation. * **********************************************************************/ void sub_bytes_inv(u8 *state_bytes) { for (u8 i=0; i<16; i++) { state_bytes[i] = _aes_sbox_inv[state_bytes[i]]; } } /********************************************************************** * * @name : shift_rows * * @note : Shift rows operation. * **********************************************************************/ void shift_rows(u8 *state_bytes) { u8 state_; // first row state_ = state_bytes[1]; state_bytes[1] = state_bytes[5]; state_bytes[5] = state_bytes[9]; state_bytes[9] = state_bytes[13]; state_bytes[13] = state_; // second row state_ = state_bytes[2]; state_bytes[2] = state_bytes[10]; state_bytes[10] = state_; state_ = state_bytes[6]; state_bytes[6] = state_bytes[14]; state_bytes[14] = state_; // third row state_ = state_bytes[15]; state_bytes[15] = state_bytes[11]; state_bytes[11] = state_bytes[7]; state_bytes[7] = state_bytes[3]; state_bytes[3] = state_; } /********************************************************************** * * @name : shift_rows_inv * * @note : Inverse shift rows operation. * **********************************************************************/ void shift_rows_inv(u8 *state_bytes) { u8 state_; // first row state_ = state_bytes[13]; state_bytes[13] = state_bytes[9]; state_bytes[9] = state_bytes[5]; state_bytes[5] = state_bytes[1]; state_bytes[1] = state_; // second row state_ = state_bytes[14]; state_bytes[14] = state_bytes[6]; state_bytes[6] = state_; state_ = state_bytes[10]; state_bytes[10] = state_bytes[2]; state_bytes[2] = state_; // third row state_ = state_bytes[3]; state_bytes[3] = state_bytes[7]; state_bytes[7] = state_bytes[11]; state_bytes[11] = state_bytes[15]; state_bytes[15] = state_; } /********************************************************************** * * @name : mix_columns * * @note : MixColumns operation. * **********************************************************************/ void mix_columns(u8 *state_bytes) { u8 sum; u8 temp[4]; for(u8 i=0; i<16; i+=4) { sum = state_bytes[i] ^ state_bytes[i+1] ^ state_bytes[i+2] ^ state_bytes[i+3]; temp[0] = _FIELD_MULT_BY_2_IN_GF8((state_bytes[i] ^ state_bytes[i+1])); temp[1] = _FIELD_MULT_BY_2_IN_GF8((state_bytes[i+1] ^ state_bytes[i+2])); temp[2] = _FIELD_MULT_BY_2_IN_GF8((state_bytes[i+2] ^ state_bytes[i+3])); temp[3] = _FIELD_MULT_BY_2_IN_GF8((state_bytes[i+3] ^ state_bytes[i])); state_bytes[i] = temp[0] ^ state_bytes[i] ^ sum; state_bytes[i+1] = temp[1] ^ state_bytes[i+1] ^ sum; state_bytes[i+2] = temp[2] ^ state_bytes[i+2] ^ sum; state_bytes[i+3] = temp[3] ^ state_bytes[i+3] ^ sum; } } /********************************************************************** * * @name : mix_columns_inv * * @note : Inverse MixColumns operation. * **********************************************************************/ void mix_columns_inv(u8 *state_bytes) { u8 sum; u8 temp[7]; for (u8 i=0; i<16; i+=4) { sum = state_bytes[i] ^ state_bytes[i+1] ^ state_bytes[i+2] ^ state_bytes[i+3]; temp[0] = _FIELD_MULT_BY_2_IN_GF8((state_bytes[i] ^ state_bytes[i+1])); temp[1] = _FIELD_MULT_BY_2_IN_GF8((state_bytes[i+1] ^ state_bytes[i+2])); temp[2] = _FIELD_MULT_BY_2_IN_GF8((state_bytes[i+2] ^ state_bytes[i+3])); temp[3] = _FIELD_MULT_BY_2_IN_GF8((state_bytes[i+3] ^ state_bytes[i])); temp[4] = _FIELD_MULT_BY_2_IN_GF8((_FIELD_MULT_BY_2_IN_GF8((state_bytes[i] ^ state_bytes[i+2])))); temp[5] = _FIELD_MULT_BY_2_IN_GF8((_FIELD_MULT_BY_2_IN_GF8((state_bytes[i+1] ^ state_bytes[i+3])))); temp[6] = _FIELD_MULT_BY_2_IN_GF8((temp[4] ^ temp[5])); state_bytes[i] = sum ^ state_bytes[i] ^ temp[0]; state_bytes[i+1] = sum ^ state_bytes[i+1] ^ temp[1]; state_bytes[i+2] = sum ^ state_bytes[i+2] ^ temp[2]; state_bytes[i+3] = sum ^ state_bytes[i+3] ^ temp[3]; state_bytes[i] ^= temp[6] ^ temp[4]; state_bytes[i+1] ^= temp[6] ^ temp[5]; state_bytes[i+2] ^= temp[6] ^ temp[4]; state_bytes[i+3] ^= temp[6] ^ temp[5]; } } /********************************************************************** * * @name : add_round_key * * @note : Add round key operation. * **********************************************************************/ void add_round_key(u8 *state_bytes, const u8 *round_key_bytes) { //add round key for (u8 i=0; i<16; i++) { state_bytes[i] ^= round_key_bytes[i]; } } /********************************************************************** * * @name : add_round_tweak * * @note : Add round tweak operation. * **********************************************************************/ void add_round_tweak(u8 *state_bytes, const u8 *exp_twk_bits) { // add round tweak for (u8 i=0; i<8; i++) { state_bytes[i] ^= exp_twk_bits[i]; } } /********************************************************************** * * @name : tweaes_enc * * @note : TweAES-128 encryption function. * **********************************************************************/ void tweaes_enc(u8 *ct, const u8 (*round_keys)[16], const u8 *twk, const u8 *pt) { u8 exp_twk[CRYPTO_EXPTWEAKBITS] = { 0 }; // expand tweak input if not equal to zero if(twk[0] != 0) { expand_tweak(&exp_twk[0], &twk[0]); } // initial key whitening memcpy(&ct[0], &pt[0], 16); add_round_key(&ct[0], round_keys[0]); // intermediate rounds for (u8 r=1; r