use JSON::XS; use Digest::MD5 'md5_hex'; use MIME::Base64; my $signing_key = '//Sw0rdFiSh//'; my $data = { first_name => 'Will', last_name => 'Smith', age => 39, }; my $json_string = encode_json( $data ); my $signature = md5_hex( $signing_key . $json_string ); my $base64_encoded = encode_base64( $json_string, '' ); # Send the encoded data and the signature in the HTML as hidden fields print <<"HTML"; HTML