5.椭圆曲线上的乘法int big_num_to_bits(unsigned long *a, unsigned char *b, int len) { unsigned long x; unsigned long w; int i = 0; int j = 0; for(i=0; i<len; i++) { x = a[i]; //printf("x=[%d]\n", x); for(j=31; j>=0; j--) { w = ((x >> j) & ...