pack() in php. Illegal hex digit warning

Question

i am having some problems using pack() in php

$currencypair = \"EUR/USD\";
$buy_sell = \"buy\";
$alert_device_token =array(\"a\",\"a\",\"b\");
$message = \"         


        

Answer 1

Use strtr(rtrim(base64_encode(pack('H*', sprintf('%u', $algo($data)))), '='), '+/', '-_') insted of using pack('H*', $value).