tmp[0] = pgm_read_byte(aes_sbox+tmp[0]);
tmp[1] = pgm_read_byte(aes_sbox+tmp[1]);
tmp[2] = pgm_read_byte(aes_sbox+tmp[2]);
tmp[3] = pgm_read_byte(aes_sbox+tmp[3]);
tmp[0] = pgm_read_byte(aes_sbox+tmp[0]);
tmp[1] = pgm_read_byte(aes_sbox+tmp[1]);
tmp[2] = pgm_read_byte(aes_sbox+tmp[2]);
tmp[3] = pgm_read_byte(aes_sbox+tmp[3]);