// gcc -O0 -Wall -Wextra -no-pie aes-distrace.c -o aes-distrace #include #include #include #include #include #include const uint8_t S[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 uint8_t mul2[256] = { 0x00, 0x02, 0x04, 0x06, 0x08, 0x0a, 0x0c, 0x0e, 0x10, 0x12, 0x14, 0x16, 0x18, 0x1a, 0x1c, 0x1e, 0x20, 0x22, 0x24, 0x26, 0x28, 0x2a, 0x2c, 0x2e, 0x30, 0x32, 0x34, 0x36, 0x38, 0x3a, 0x3c, 0x3e, 0x40, 0x42, 0x44, 0x46, 0x48, 0x4a, 0x4c, 0x4e, 0x50, 0x52, 0x54, 0x56, 0x58, 0x5a, 0x5c, 0x5e, 0x60, 0x62, 0x64, 0x66, 0x68, 0x6a, 0x6c, 0x6e, 0x70, 0x72, 0x74, 0x76, 0x78, 0x7a, 0x7c, 0x7e, 0x80, 0x82, 0x84, 0x86, 0x88, 0x8a, 0x8c, 0x8e, 0x90, 0x92, 0x94, 0x96, 0x98, 0x9a, 0x9c, 0x9e, 0xa0, 0xa2, 0xa4, 0xa6, 0xa8, 0xaa, 0xac, 0xae, 0xb0, 0xb2, 0xb4, 0xb6, 0xb8, 0xba, 0xbc, 0xbe, 0xc0, 0xc2, 0xc4, 0xc6, 0xc8, 0xca, 0xcc, 0xce, 0xd0, 0xd2, 0xd4, 0xd6, 0xd8, 0xda, 0xdc, 0xde, 0xe0, 0xe2, 0xe4, 0xe6, 0xe8, 0xea, 0xec, 0xee, 0xf0, 0xf2, 0xf4, 0xf6, 0xf8, 0xfa, 0xfc, 0xfe, 0x1b, 0x19, 0x1f, 0x1d, 0x13, 0x11, 0x17, 0x15, 0x0b, 0x09, 0x0f, 0x0d, 0x03, 0x01, 0x07, 0x05, 0x3b, 0x39, 0x3f, 0x3d, 0x33, 0x31, 0x37, 0x35, 0x2b, 0x29, 0x2f, 0x2d, 0x23, 0x21, 0x27, 0x25, 0x5b, 0x59, 0x5f, 0x5d, 0x53, 0x51, 0x57, 0x55, 0x4b, 0x49, 0x4f, 0x4d, 0x43, 0x41, 0x47, 0x45, 0x7b, 0x79, 0x7f, 0x7d, 0x73, 0x71, 0x77, 0x75, 0x6b, 0x69, 0x6f, 0x6d, 0x63, 0x61, 0x67, 0x65, 0x9b, 0x99, 0x9f, 0x9d, 0x93, 0x91, 0x97, 0x95, 0x8b, 0x89, 0x8f, 0x8d, 0x83, 0x81, 0x87, 0x85, 0xbb, 0xb9, 0xbf, 0xbd, 0xb3, 0xb1, 0xb7, 0xb5, 0xab, 0xa9, 0xaf, 0xad, 0xa3, 0xa1, 0xa7, 0xa5, 0xdb, 0xd9, 0xdf, 0xdd, 0xd3, 0xd1, 0xd7, 0xd5, 0xcb, 0xc9, 0xcf, 0xcd, 0xc3, 0xc1, 0xc7, 0xc5, 0xfb, 0xf9, 0xff, 0xfd, 0xf3, 0xf1, 0xf7, 0xf5, 0xeb, 0xe9, 0xef, 0xed, 0xe3, 0xe1, 0xe7, 0xe5 }; const uint8_t RCON[11] = { 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36 }; #define MC(a,b,c,d) do { \ const uint8_t aa = mul2[(a)] ^ mul2[(b)] ^ (b) ^ (c) ^ (d); \ const uint8_t bb = (a) ^ mul2[(b)] ^ mul2[(c)] ^ (c) ^ (d); \ const uint8_t cc = (a) ^ (b) ^ mul2[(c)] ^ mul2[(d)] ^ (d); \ const uint8_t dd = mul2[(a)] ^ (a) ^ (b) ^ (c) ^ mul2[(d)]; \ (a) = aa; \ (b) = bb; \ (c) = cc; \ (d) = dd; \ } while(0); void keyExpansion(uint8_t rk[11][4][4], const uint8_t* key) { for (int j = 0; j < 4; ++j) { rk[0][0][j] = key[4 * j + 0]; rk[0][1][j] = key[4 * j + 1]; rk[0][2][j] = key[4 * j + 2]; rk[0][3][j] = key[4 * j + 3]; } for (int i = 1; i < 11; ++i) { /* First column */ rk[i][0][0] = rk[i - 1][0][0] ^ S[rk[i - 1][1][3]] ^ RCON[i]; rk[i][1][0] = rk[i - 1][1][0] ^ S[rk[i - 1][2][3]]; rk[i][2][0] = rk[i - 1][2][0] ^ S[rk[i - 1][3][3]]; rk[i][3][0] = rk[i - 1][3][0] ^ S[rk[i - 1][0][3]]; /* Second column */ rk[i][0][1] = rk[i - 1][0][1] ^ rk[i][0][0]; rk[i][1][1] = rk[i - 1][1][1] ^ rk[i][1][0]; rk[i][2][1] = rk[i - 1][2][1] ^ rk[i][2][0]; rk[i][3][1] = rk[i - 1][3][1] ^ rk[i][3][0]; /* Third column */ rk[i][0][2] = rk[i - 1][0][2] ^ rk[i][0][1]; rk[i][1][2] = rk[i - 1][1][2] ^ rk[i][1][1]; rk[i][2][2] = rk[i - 1][2][2] ^ rk[i][2][1]; rk[i][3][2] = rk[i - 1][3][2] ^ rk[i][3][1]; /* Fourth column */ rk[i][0][3] = rk[i - 1][0][3] ^ rk[i][0][2]; rk[i][1][3] = rk[i - 1][1][3] ^ rk[i][1][2]; rk[i][2][3] = rk[i - 1][2][3] ^ rk[i][2][2]; rk[i][3][3] = rk[i - 1][3][3] ^ rk[i][3][2]; } } void AddRoundKey(uint8_t r, uint8_t s[4][4], const uint8_t rk[11][4][4]) { /* First column */ s[0][0] ^= rk[r][0][0]; s[1][0] ^= rk[r][1][0]; s[2][0] ^= rk[r][2][0]; s[3][0] ^= rk[r][3][0]; /* Second column */ s[0][1] ^= rk[r][0][1]; s[1][1] ^= rk[r][1][1]; s[2][1] ^= rk[r][2][1]; s[3][1] ^= rk[r][3][1]; /* Third column */ s[0][2] ^= rk[r][0][2]; s[1][2] ^= rk[r][1][2]; s[2][2] ^= rk[r][2][2]; s[3][2] ^= rk[r][3][2]; /* Fourth column */ s[0][3] ^= rk[r][0][3]; s[1][3] ^= rk[r][1][3]; s[2][3] ^= rk[r][2][3]; s[3][3] ^= rk[r][3][3]; } void SubBytes_ShiftRows(uint8_t s[4][4]) { uint8_t t[4][4]; for (int i = 0; i < 4; ++i) { t[i][0] = s[i][0]; t[i][1] = s[i][1]; t[i][2] = s[i][2]; t[i][3] = s[i][3]; } for (int i = 0; i < 4; ++i) { s[i][0] = S[ t[i][(i + 0) % 4] ]; s[i][1] = S[ t[i][(i + 1) % 4] ]; s[i][2] = S[ t[i][(i + 2) % 4] ]; s[i][3] = S[ t[i][(i + 3) % 4] ]; } } void MixColumns(uint8_t s[4][4]) { MC(s[0][0], s[1][0], s[2][0], s[3][0]); MC(s[0][1], s[1][1], s[2][1], s[3][1]); MC(s[0][2], s[1][2], s[2][2], s[3][2]); MC(s[0][3], s[1][3], s[2][3], s[3][3]); } void bytes2state(const uint8_t *b, uint8_t s[4][4]) { for (int j = 0; j < 4; ++j) { s[0][j] = b[4 * j + 0]; s[1][j] = b[4 * j + 1]; s[2][j] = b[4 * j + 2]; s[3][j] = b[4 * j + 3]; } } void state2bytes(uint8_t *b, const uint8_t s[4][4]) { for (int j = 0; j < 4; ++j) { b[4 * j + 0] = s[0][j]; b[4 * j + 1] = s[1][j]; b[4 * j + 2] = s[2][j]; b[4 * j + 3] = s[3][j]; } } void AES128(const uint8_t rk[11][4][4], uint8_t *input) { uint8_t s[4][4]; bytes2state(input, s); AddRoundKey(0, s, rk); for (uint8_t r = 1; ; ++r) { SubBytes_ShiftRows(s); if (r == 10) { AddRoundKey(r, s, rk); break; } MixColumns(s); AddRoundKey(r, s, rk); } state2bytes(input, s); } void ECB(const uint8_t *key, uint8_t *input, const size_t length) { uint8_t rk[11][4][4]; keyExpansion(rk, key); for (unsigned int k = 0; k < length; k += 16) { AES128(rk, input + k); } } int main() { int fd; ssize_t nbRead; uint8_t key[16] = {0}; uint8_t challenge[16] = {0}; /* Read a random 128-bit key */ fd = open("/dev/random", O_RDONLY); if (!fd) { perror("open"); exit(EXIT_FAILURE); } nbRead = read(fd, key, sizeof(key)); if (nbRead < 0) { perror("read (key)"); exit(EXIT_FAILURE); } close(fd); /* Read a 16-byte challenge from stdin */ nbRead = read(STDIN_FILENO, challenge, sizeof(challenge)); if (nbRead < 0) { perror("read (challenge)"); exit(EXIT_FAILURE); } /* Encrypt the challenge */ ECB(key, challenge, sizeof(challenge)); /* Display the encrypted challenge */ for (unsigned int j = 0; j < sizeof(challenge); ++j) { printf("%02x", challenge[j]); } printf("\n"); /* The end */ return EXIT_SUCCESS; }