diff --git a/plugins/auth_internal/init.php b/plugins/auth_internal/init.php
index b66f7719b..1bf3d6a24 100644
--- a/plugins/auth_internal/init.php
+++ b/plugins/auth_internal/init.php
@@ -130,7 +130,7 @@ class Auth_Internal extends Auth_Base {
 		}
 
 		if ($login) {
-			$try_user_id = $this->find_user_by_login($login);
+			$try_user_id = UserHelper::find_user_by_login($login);
 
 			if ($try_user_id) {
 				return $this->check_password($try_user_id, $password);
@@ -140,6 +140,14 @@ class Auth_Internal extends Auth_Base {
 		return false;
 	}
 
+	/**
+	 * @param int $owner_uid
+	 * @param string $password
+	 * @param string $service
+	 * @return int|false (false if failed, user id otherwise)
+	 * @throws PDOException
+	 * @throws Exception
+	 */
 	function check_password(int $owner_uid, string $password, string $service = '') {
 
 		$user = ORM::for_table('ttrss_users')->find_one($owner_uid);
@@ -203,7 +211,7 @@ class Auth_Internal extends Auth_Base {
 		return false;
 	}
 
-	function change_password($owner_uid, $old_password, $new_password) {
+	function change_password(int $owner_uid, string $old_password, string $new_password) : string {
 
 		if ($this->check_password($owner_uid, $old_password)) {
 
@@ -246,7 +254,15 @@ class Auth_Internal extends Auth_Base {
 		}
 	}
 
-	private function check_app_password($login, $password, $service) {
+	/**
+	 * @param string $login
+	 * @param string $password
+	 * @param string $service
+	 * @return false|int (false if failed, user id otherwise)
+	 * @throws PDOException
+	 * @throws Exception
+	 */
+	private function check_app_password(string $login, string $password, string $service) {
 		$sth = $this->pdo->prepare("SELECT p.id, p.pwd_hash, u.id AS uid
 			FROM ttrss_app_passwords p, ttrss_users u
 			WHERE p.owner_uid = u.id AND LOWER(u.login) = LOWER(?) AND service = ?");
diff --git a/plugins/auth_remote/init.php b/plugins/auth_remote/init.php
index 35ee9e31d..9c15d3368 100644
--- a/plugins/auth_remote/init.php
+++ b/plugins/auth_remote/init.php
@@ -12,7 +12,7 @@ class Auth_Remote extends Auth_Base {
 		$host->add_hook($host::HOOK_AUTH_USER, $this);
 	}
 
-	function get_login_by_ssl_certificate() {
+	function get_login_by_ssl_certificate() : string {
 		$cert_serial = Pref_Prefs::_get_ssl_certificate_id();
 
 		if ($cert_serial) {