I took your suggestion as a challenge. Here is the best I could do. It probably is not what you had in mind.

use strict;
use warnings;
use Test::More tests=>1;

my $Origin_Host_CER="example.me";
my $required = "6578616d706c652e6d650000";

my $length = 4*int((length($Origin_Host_CER)+3)/4);
my $result = unpack('H*', pack("Z$length", $Origin_Host_CER));

is($result, $required, 'AVP String');
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