while (i-- > 0)
while (i--)
int BN_bn2bin(const BIGNUM *a, unsigned char *to)	{	int n,i;	BN_ULONG l;	bn_check_top(a);	n=i=BN_num_bytes(a);	while (i-- > 0)		{		l=a->d[i/BN_BYTES];		*(to++)=(unsigned char)(l>>(8*(i%BN_BYTES)))&0xff;		}	return(n);	}