perl/mul.pl

   1 #!/usr/local/bin/perl
   2
   3 use ExtUtils::testlib;
   4
   5 use SSLeay;
   6
   7
   8 sub mul
   9         {
  10         my($ab,$cd,$num)=@_;
  11
  12         if ($num <= 4096)
  13                 {
  14                 return($ab*$cd);
  15                 }
  16         else
  17                 {
  18                 my($a,$b,$c,$d,$n,$ac,$bd,$m,$t1,$t2);
  19
  20                 $n=$num/2;
  21
  22                 $a=$ab->mask_bits($n);
  23                 $b=$ab->rshift($n);
  24                 $c=$cd->mask_bits($n);
  25                 $d=$cd->rshift($n);
  26
  27                 $t1=($b-$a);
  28                 $t2=($c-$d);
  29                 $m= &mul($t1,$t2,$n);
  30                 $ac=&mul($a,$c,$n);
  31                 $bd=&mul($b,$d,$n);
  32                 $m=$m+$ac+$bd;
  33                 $m=$m->lshift($n);
  34                 $bd=$bd->lshift($num);
  35
  36                 $r=$ac+$m+$bd;
  37                 return($r);
  38                 }
  39         }
  40
  41 $num=4096*32;
  42 $a=SSLeay::BN::rand($num);
  43 $b=SSLeay::BN::rand($num);
  44
  45 #for (1 .. 10)
  46         {
  47         $r=&mul($a,$b,$num);
  48         }
  49
  50 #for (1 .. 10)
  51         {
  52         $rr=$a*$b;
  53         }
  54
  55 $res=$rr-$r;
  56 print $res->bn2hex()."\n";