Fix #6103

components/security/secure_tools.rst

@@ -1,47 +1,39 @@
-Securely Generating Random Numbers
+Securely Generating Random Strings 
 ==================================
 
 The Symfony Security component comes with a collection of nice utilities
 related to security. These utilities are used by Symfony, but you should
 also use them if you want to solve the problem they address.
 
-Generating a Secure random Number
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+Generating a Secure random
+~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Whenever you need to generate a secure random number, you are highly
-encouraged to use the Symfony
-:class:`Symfony\\Component\\Security\\Core\\Util\\SecureRandom` class::
+encouraged to use the 
+:phpfunction:`random_bytes` function::
 
-    use Symfony\Component\Security\Core\Util\SecureRandom;
+    $random = random_bytes(10);
 
-    $generator = new SecureRandom();
-    $random = $generator->nextBytes(10);
+The function returns a random string, suitable for cryptographic use, of
+the number bytes passed as an argument (10 in the above example).
 
-The
-:method:`Symfony\\Component\\Security\\Core\\Util\\SecureRandom::nextBytes`
-method returns a random string composed of the number of characters passed as
-an argument (10 in the above example).
-
-The SecureRandom class works better when OpenSSL is installed. But when it's
-not available, it falls back to an internal algorithm, which needs a seed file
-to work correctly. Just pass a file name to enable it::
-
-    use Symfony\Component\Security\Core\Util\SecureRandom;
-
-    $generator = new SecureRandom('/some/path/to/store/the/seed.txt');
+.. note::
 
-    $random = $generator->nextBytes(10);
-    $hashedRandom = md5($random); // see tip below
+    PHP 7 and up provide the ``random_bytes()`` function natively, for older
+    versions of PHP a polyfill is provided by the `Symfony Polyfill Component`_
+    and the `paragonie/random_compat package`_.
 
-.. note::
+.. versionadded:: 2.8
 
-    If you're using the Symfony Framework, you can get a secure random number
-    generator via the ``security.secure_random`` service.
+    The `paragonie/random_compat package`_ was added as a dependancy of the Symfony Security Component in 2.8. You will need to manually require the package as a dependancy of your project in versions of Symfony prior to 2.8.
 
 .. tip::
 
-    The ``nextBytes()`` method returns a binary string which may contain the
+    The ``random_bytes()`` function returns a binary string which may contain the
     ``\0`` character. This can cause trouble in several common scenarios, such
     as storing this value in a database or including it as part of the URL. The
-    solution is to hash the value returned by ``nextBytes()`` (to do that, you
+    solution is to hash the value returned by ``random_bytes()`` (to do that, you
     can use a simple ``md5()`` PHP function).
+
+.. _`Symfony Polyfill Component`: https://github.com/symfony/polyfill
+.. _`paragonie/random_compat package`: https://github.com/paragonie/random_compat