diff --git a/src/inc/security.php b/src/inc/security.php
new file mode 100644
index 0000000..1d3159b
--- /dev/null
+++ b/src/inc/security.php
@@ -0,0 +1,362 @@
+<?php
+class security {
+  const HYPERADMIN = 0;
+  const ADMIN = 2;
+  /*const SYSTEM_REVIEWER = 5;
+  const LOG_REVIEWER = 7;*/
+  const WORKER = 10;
+  const UNKNOWN = 1000;
+
+  const METHOD_UNSPECIFICED = -1;
+  const METHOD_REDIRECT = 0;
+  const METHOD_NOTFOUND = 1;
+
+  const PARAM_ISSET = 1;
+  const PARAM_NEMPTY = 2;
+  const PARAM_ISEMAIL = 4;
+  const PARAM_ISDATE = 8;
+  const PARAM_ISINT = 16;
+  const PARAM_ISTIME = 32;
+  const PARAM_ISARRAY = 64;
+  const PARAM_ISEMAILOREMPTY = 128;
+
+  const SIGNIN_STATE_SIGNED_IN = 0;
+  const SIGNIN_STATE_NEEDS_SECOND_FACTOR = 1;
+  const SIGNIN_STATE_SIGNED_OUT = 2;
+  const SIGNIN_STATE_THROTTLED = 3;
+
+  public static $types = [
+    10 => "Trabajador",
+    /*7 => "Revisor de logs",
+    5 => "Revisor del sistema",*/
+    2 => "Administrador",
+    0 => "Hiperadministrador"
+  ];
+
+  public static $automatedChecks = [self::PARAM_ISSET, self::PARAM_NEMPTY, self::PARAM_ISEMAIL, self::PARAM_ISDATE, self::PARAM_ISINT, self::PARAM_ISTIME, self::PARAM_ISARRAY, self::PARAM_ISEMAILOREMPTY];
+
+  public static $passwordHelperText = "La contraseña debe tener como mínimo 8 caracteres y una letra mayúscula.";
+
+  public static function go($page) {
+    global $conf;
+
+    if ($conf["superdebug"]) {
+      echo "Redirects are not enabled. We would like to redirect you here: <a href='".self::htmlsafe($page)."'>".self::htmlsafe($page)."</a>";
+    } else {
+      header("Location: ".$page);
+    }
+
+    exit();
+  }
+
+  public static function goHome() {
+    self::go("index.php");
+  }
+
+  public static function notFound() {
+    header('HTTP/1.0 404 Not Found');
+    exit();
+  }
+
+  public static function isSignedIn() {
+    global $_SESSION;
+
+    return isset($_SESSION["id"]);
+  }
+
+  public static function check() {
+    if (!self::isSignedIn()) {
+      self::goHome();
+    }
+  }
+
+  public static function userType() {
+    global $_SESSION, $con;
+
+    if (!isset($_SESSION["id"])) {
+      return self::UNKNOWN;
+    }
+
+    $query = mysqli_query($con, "SELECT type FROM people WHERE id = ".(int)$_SESSION["id"]);
+
+    if (!mysqli_num_rows($query)) {
+      return self::UNKNOWN;
+    }
+
+    $row = mysqli_fetch_assoc($query);
+
+    return $row["type"];
+  }
+
+  public static function isAllowed($type) {
+    $userType = (self::isSignedIn() ? self::userType() : self::UNKNOWN);
+
+    return $userType <= $type;
+  }
+
+  public static function denyUseMethod($method = self::METHOD_REDIRECT) {
+    if ($method === self::METHOD_NOTFOUND) {
+      self::notFound();
+    } else { // self::METHOD_REDIRECT or anything else
+      self::goHome();
+    }
+  }
+
+  public static function checkType($type, $method = self::METHOD_REDIRECT) {
+    if (!self::isAllowed($type)) {
+      self::denyUseMethod($method);
+    }
+  }
+
+  public static function checkWorkerUIEnabled() {
+    global $conf;
+
+    if (self::userType() >= self::WORKER && !$conf["enableWorkerUI"]) {
+      self::go("index.php?msg=unsupported");
+    }
+  }
+
+  // Code from https://timoh6.github.io/2015/05/07/Rate-limiting-web-application-login-attempts.html
+  private static function getIpAddresses() {
+    $ips = [];
+    $ips["remoteIp"] = inet_pton($_SERVER['REMOTE_ADDR']); // inet_pton can handle both IPv4 and IPv6 addresses, treat IPv6 addresses as /64 or /56 blocks.
+    $ips["remoteIpBlock"] = long2ip(ip2long($_SERVER['REMOTE_ADDR']) & 0xFFFFFF00); // Something like this to turn the last octet of IPv4 address into a 0.
+    return $ips;
+  }
+
+  public static function recordLoginAttempt($username) {
+    global $con;
+
+    $susername = db::sanitize($username);
+
+    $ips = self::getIpAddresses();
+    $sremoteIp = db::sanitize($ips["remoteIp"]);
+    $sremoteIpBlock = db::sanitize($ips["remoteIpBlock"]);
+
+    return mysqli_query($con, "INSERT INTO signinattempts (username, remoteip, remoteipblock, signinattempttime) VALUES ('$susername', '$sremoteIp', '$sremoteIpBlock', NOW())");
+  }
+
+  public static function getRateLimitingCounts($username) {
+    global $con, $conf;
+
+    $susername = db::sanitize($username);
+
+    $ips = self::getIpAddresses();
+    $sremoteIp = db::sanitize($ips["remoteIp"]);
+    $sremoteIpBlock = db::sanitize($ips["remoteIpBlock"]);
+
+    $query = mysqli_query($con, "SELECT
+        COUNT(*) AS global_attempt_count,
+        IFNULL(SUM(CASE WHEN remoteip = '$sremoteIp' THEN 1 ELSE 0 END), 0) AS ip_attempt_count,
+        IFNULL(SUM(CASE WHEN (remoteipblock = '$sremoteIpBlock') THEN 1 ELSE 0 END), 0) AS ip_block_attempt_count,
+        (SELECT COUNT(DISTINCT remoteipblock) FROM signinattempts WHERE username = '$susername' AND signinattempttime >= (NOW() - INTERVAL 10 SECOND )) AS ip_blocks_per_username_attempt_count,
+        (SELECT COUNT(*) FROM signinattempts WHERE username = '$susername' AND signinattempttime >= (NOW() - INTERVAL 10 SECOND )) AS username_attempt_count
+      FROM signinattempts
+      WHERE signinattempttime >= (NOW() - INTERVAL 10 second)");
+
+    if ($query === false) return false;
+
+    return mysqli_fetch_assoc($query);
+  }
+
+  public static function isSignInThrottled($username) {
+    global $conf;
+
+    $count = self::getRateLimitingCounts($username);
+
+    if ($count["global_attempt_count"] >= $conf["signinThrottling"]["attemptCountLimit"]["global"] ||
+        $count["ip_attempt_count"] >= $conf["signinThrottling"]["attemptCountLimit"]["ip"] ||
+        $count["ip_block_attempt_count"] >= $conf["signinThrottling"]["attemptCountLimit"]["ipBlock"] ||
+        $count["ip_blocks_per_username_attempt_count"] >= $conf["signinThrottling"]["attemptCountLimit"]["ipBlocksPerUsername"] ||
+        $count["username_attempt_count"] >= $conf["signinThrottling"]["attemptCountLimit"]["username"]) {
+      return true;
+    }
+
+    if (!self::recordLoginAttempt($username)) {
+      echo "There was an unexpected error, so you could not be authenticated. Please contact me@avm99963.com and let them know of the error. (2)";
+      exit();
+    }
+
+    return false;
+  }
+
+  public static function isUserPassword($username, $password) {
+    global $con, $_SESSION;
+
+    $susername = db::sanitize($username);
+    $query = mysqli_query($con, "SELECT id, password FROM people WHERE ".($username === false ? "id = ".(int)$_SESSION["id"] : "username = '".$susername."'"));
+
+    if (!mysqli_num_rows($query)) {
+      return false;
+    }
+
+    $row = mysqli_fetch_assoc($query);
+
+    if (!password_verify($password, $row["password"])) {
+      return false;
+    }
+
+    return $row["id"];
+  }
+
+  public static function signIn($username, $password) {
+    global $_SESSION;
+
+    if (self::isSignInThrottled($username)) return self::SIGNIN_STATE_THROTTLED;
+
+    $id = self::isUserPassword($username, $password);
+
+    if ($id !== false) {
+      if (secondFactor::isEnabled($id)) {
+        $_SESSION["firstfactorid"] = $id;
+        return self::SIGNIN_STATE_NEEDS_SECOND_FACTOR;
+      } else {
+        $_SESSION["id"] = $id;
+        return self::SIGNIN_STATE_SIGNED_IN;
+      }
+    }
+
+    return self::SIGNIN_STATE_SIGNED_OUT;
+  }
+
+  public static function redirectAfterSignIn() {
+    global $conf;
+
+    if (self::isAllowed(self::ADMIN)) {
+      self::changeActiveView(visual::VIEW_ADMIN);
+      self::go("home.php");
+    } else {
+      self::changeActiveView(visual::VIEW_WORKER);
+      self::go(($conf["enableWorkerUI"] ? "workerhome.php" : "index.php?msg=unsupported"));
+    }
+  }
+
+  public static function logout() {
+    global $_SESSION;
+
+    session_destroy();
+  }
+
+  public static function htmlsafe($string) {
+    if ($string === null) return '';
+    return htmlspecialchars((string)$string);
+  }
+
+  private static function failedCheckParams($parameter, $method, $check) {
+    global $conf;
+
+    if ($conf["superdebug"]) {
+      echo "Failed check ".(int)$check." using parameter '".self::htmlsafe($parameter)."' with method ".self::htmlsafe($method).".<br>";
+    }
+  }
+
+  public static function checkParam($param, $check) {
+    if ($check == self::PARAM_NEMPTY && empty($param)) {
+      return false;
+    }
+
+    if ($check == self::PARAM_ISEMAIL && filter_var($param, FILTER_VALIDATE_EMAIL) === false) {
+      return false;
+    }
+
+    if ($check == self::PARAM_ISDATE && preg_match("/^[0-9]+-[0-9]+-[0-9]+$/", $param) !== 1) {
+      return false;
+    }
+
+    if ($check == self::PARAM_ISINT && filter_var($param, FILTER_VALIDATE_INT) === false) {
+      return false;
+    }
+
+    if ($check == self::PARAM_ISTIME) {
+      if (preg_match("/^[0-9]+:[0-9]+$/", $param) !== 1) return false;
+
+      $time = explode(":", $param);
+      if ((int)$time[0] >= 24 || (int)$time[1] >= 60) return false;
+    }
+
+    if ($check == self::PARAM_ISARRAY) {
+      // Check whether the parameter is an array
+      if (is_array($param) === false) return false;
+
+      // Check that it is not a multidimensional array (we don't want that for any parameter!)
+      foreach ($param as &$el) {
+        if (is_array($el)) return false;
+      }
+    }
+
+    if ($check == self::PARAM_ISEMAILOREMPTY && $param !== "" && filter_var($param, FILTER_VALIDATE_EMAIL) === false) {
+      return false;
+    }
+
+    return true;
+  }
+
+  public static function checkParams($method, $parameters, $forceDisableDebug = false) {
+    global $_POST, $_GET;
+
+    if (!in_array($method, ["GET", "POST"])) {
+      return false;
+    }
+
+    foreach ($parameters as $p) {
+      if (!$p[1]) {
+        continue;
+      }
+
+      if (($method == "POST" && !isset($_POST[$p[0]])) || ($method == "GET" && !isset($_GET[$p[0]]))) {
+        if (!$forceDisableDebug) self::failedCheckParams($p[0], $method, self::PARAM_ISSET);
+        return false;
+      }
+
+      $value = ($method == "POST" ? $_POST[$p[0]] : $_GET[$p[0]]);
+
+      foreach (self::$automatedChecks as $check) {
+        if (($p[1] & $check) && !self::checkParam($value, $check)) {
+          if (!$forceDisableDebug) self::failedCheckParams($p[0], $method, $check);
+          return false;
+        }
+      }
+    }
+
+    return true;
+  }
+
+  public static function existsType($type) {
+    $types = array_keys(self::$types);
+
+    return in_array($type, $types);
+  }
+
+  public static function getActiveView() {
+    global $_SESSION;
+
+    if (!self::isAllowed(self::ADMIN)) {
+      return visual::VIEW_WORKER;
+    }
+
+    return (!isset($_SESSION["activeView"]) ? visual::VIEW_ADMIN : $_SESSION["activeView"]);
+  }
+
+  public static function isAdminView() {
+    return (self::getActiveView() === visual::VIEW_ADMIN);
+  }
+
+  public static function changeActiveView($view) {
+    $_SESSION["activeView"] = $view;
+  }
+
+  public static function passwordIsGoodEnough($password) {
+    return (strlen($password) >= 8 && preg_match('/[A-Z]/', $password));
+  }
+
+  public static function cleanSignInAttempts($retentionDays = "DEFAULT") {
+    global $con, $conf;
+
+    if ($retentionDays === "DEFAULT") $retentionDays = $conf["signinThrottling"]["retentionDays"];
+
+    $sretentionDays = (int)$retentionDays;
+    if ($retentionDays < 0) return false;
+
+    return mysqli_query($con, "DELETE FROM signinattempts WHERE signinattempttime < (NOW() - INTERVAL $sretentionDays DAY)");
+  }
+}