IBAA_Byte
static u_char IBAA_Byte(struct ibaa_state *ibaa);
*iptr = ((*iptr << 3) | (*iptr >> 29)) + (val ^ (IBAA_Byte(ibaa) & 15));
((u_char *)buf)[i] = IBAA_Byte(&state->ibaa);
((u_char *)buf)[j] ^= IBAA_Byte(&state->ibaa);