utils.php

<?php
require_once(dirname(dirname(dirname(dirname(__FILE__)))) . '/wp-load.php');

function social_connect_get_user_by_meta($meta_key, $meta_value) {
  global $wpdb;
  $sql = "SELECT user_id FROM $wpdb->usermeta WHERE meta_key = '%s' AND meta_value = '%s'";
  return $wpdb->get_var($wpdb->prepare($sql, $meta_key, $meta_value));
}

function social_connect_generate_signature($data) {
  return hash('SHA256', AUTH_KEY . $data);
}

function social_connect_verify_signature($data, $signature, $redirect_to) {
  $generated_signature = social_connect_generate_signature($data);
  if($generated_signature != $signature) {
    wp_safe_redirect($redirect_to);
    exit();
  }
}

?>