- base64_decode: documentation ( source)
<?php
$text = '{"showpassword":"no","bgcolor","#000000"}';
$key = base64_decode('ClVLIh4ASCsCBE8lAxMacFMZV2hdVVotEhhUJQNVAmhSRwh6QUcIaAw=');
$outText = '';
for($i=0;$i<strlen($text);$i++) {
$outText .= $text[$i] ^ $key[$i % strlen($key)];
}
echo $outText;
?>