set_mask(); while () { chomp; $in = substr($_, 0, 40); if ($in =~ /^[0-9a-f]/i ) { # check that it's valid hex my $in_bits = unpack("B*", pack("H40",$in)); my %offsets ; for(my $j=0;$j<20;$j++) { # each of 20 bitmasks $offsets{calc_vector($in_bits,$bits[$j])} = 1; } foreach my $k (sort {$a <=> $b} (keys %offsets) ) { print "$k\n"; } } } print "\n"; exit; #-------- sub set_mask { $mask[0]="FFFF804020100804020100804020100804000102"; $mask[10]=reverse($mask[0]); $bits[0] = unpack("B*", pack("H40",$mask[0])); $bits[10] = unpack("B*", pack("H40",$mask[10])); for (my $i=1;$i<10;$i++) { $mask[$i] = substr($mask[$i-1],36,4) . substr($mask[$i-1],0,36) ; $mask[10+$i] = substr($mask[10+$i-1],36,4) . substr($mask[10+$i-1],0,36) ; $bits[$i] = unpack("B*", pack("H40",$mask[$i])); $bits[10+$i] = unpack("B*", pack("H40",$mask[10+$i])); } return(0); } sub calc_vector { my $input = shift; my $mask = shift; my $vecs = ""; for (my $i=0;$i<160;$i++) { if (substr($mask,$i,1) eq "1") { $vecs .= substr($input,$i,1); } } return(hex(unpack("H*", pack("B32",$vecs)))); }