- var_dump: documentation ( source)
- json_decode: documentation ( source)
<?php
$received = strval(json_decode('{"signature":"TF\\/Ga+6JJBgs236TyTbvxZoXmsI="}')->signature);
$my = "TF/Ga+6JJBgs236TyTbvxZoXmsI=";
var_dump([
$received,
$my,
$received == $my
]);