$k= "0802020501020401054a2b020154212d01050c030d5230150d064c28190208060d";
@r=unpack('C*', pack('H*',$k)); for (1..shift(@r)){$n[$q+= shift(@r)]=1;}
for(@r){if($n[$t]){$_=-$_};$t++;print chr($o+=$_);}#sig-relation.04.20.02