my $chapid3= '\027';
my $chapchalange3= '\340\174\012\314\214\070\070\231\377\005\016\132\270\024\241\163';
s/\\(\d{3})/chr(oct($1))/eg for $chapid3, $chapchalange3;

print "\nExample2=".Digest::MD5::md5_hex($chapid3."AAA".$chapchalange3);