Base API, and more solid key and check

app/src/Service/Login.php

@@ -47,6 +47,14 @@ class Login
         }
         return $login->user;
     }
+    public function getToken(): string
+    {
+        return implode($this->cookie_separator, [$this->selector, $this->token]);
+    }
+    public function getSeparator(): string
+    {
+        return $this->cookie_separator;
+    }
     public function validateUser(Model\User $user, string $encryptedPassword): bool
     {
         list($passphrase, $encrypted) = $this->splitPassword($encryptedPassword);