diff --git a/src/Grant/AbstractGrant.php b/src/Grant/AbstractGrant.php
index 39fbf543..c18058f8 100644
--- a/src/Grant/AbstractGrant.php
+++ b/src/Grant/AbstractGrant.php
@@ -23,7 +23,6 @@ use League\OAuth2\Server\Exception\OAuthServerException;
 use League\OAuth2\Server\Repositories\AccessTokenRepositoryInterface;
 use League\OAuth2\Server\Repositories\ClientRepositoryInterface;
 use League\OAuth2\Server\Repositories\ScopeRepositoryInterface;
-use League\OAuth2\Server\Utils\SecureKey;
 use Psr\Http\Message\ServerRequestInterface;
 
 /**
@@ -310,7 +309,7 @@ abstract class AbstractGrant implements GrantTypeInterface
         array $scopes = []
     ) {
         $accessToken = new AccessTokenEntity();
-        $accessToken->setIdentifier(SecureKey::generate());
+        $accessToken->setIdentifier($this->generateUniqueIdentifier());
         $accessToken->setExpiryDateTime((new \DateTime())->add($tokenTTL));
         $accessToken->setClient($client);
         $accessToken->setUserIdentifier($userIdentifier);
@@ -342,7 +341,7 @@ abstract class AbstractGrant implements GrantTypeInterface
         array $scopes = []
     ) {
         $authCode = new AuthCodeEntity();
-        $authCode->setIdentifier(SecureKey::generate());
+        $authCode->setIdentifier($this->generateUniqueIdentifier());
         $authCode->setExpiryDateTime((new \DateTime())->add($tokenTTL));
         $authCode->setClient($client);
         $authCode->setUserIdentifier($userIdentifier);
@@ -363,13 +362,35 @@ abstract class AbstractGrant implements GrantTypeInterface
     protected function issueRefreshToken(AccessTokenEntity $accessToken)
     {
         $refreshToken = new RefreshTokenEntity();
-        $refreshToken->setIdentifier(SecureKey::generate());
+        $refreshToken->setIdentifier($this->generateUniqueIdentifier());
         $refreshToken->setExpiryDateTime((new \DateTime())->add($this->refreshTokenTTL));
         $refreshToken->setAccessToken($accessToken);
 
         return $refreshToken;
     }
 
+    /**
+     * Generate a new unique identifier
+     *
+     * @param int $length
+     *
+     * @return string
+     *
+     * @throws \League\OAuth2\Server\Exception\OAuthServerException
+     */
+    protected function generateUniqueIdentifier($length = 40)
+    {
+        try {
+            return bin2hex(random_bytes($length));
+        } catch (\TypeError $e) {
+            throw OAuthServerException::serverError('An unexpected error has occurred');
+        } catch (\Error $e) {
+            throw OAuthServerException::serverError('An unexpected error has occurred');
+        } catch (\Exception $e) {
+            throw OAuthServerException::serverError('Could not generate a random string');
+        }
+    }
+
     /**
      * @inheritdoc
      */
diff --git a/src/Utils/SecureKey.php b/src/Utils/SecureKey.php
deleted file mode 100644
index f5078bbf..00000000
--- a/src/Utils/SecureKey.php
+++ /dev/null
@@ -1,47 +0,0 @@
-<?php
-/**
- * OAuth 2.0 Secure key generator
- *
- * @package     php-loep/oauth2-server
- * @author      Alex Bilbie <hello@alexbilbie.com>
- * @copyright   Copyright (c) 2013 PHP League of Extraordinary Packages
- * @license     http://mit-license.org/
- * @link        http://github.com/php-loep/oauth2-server
- */
-
-namespace League\OAuth2\Server\Utils;
-
-use League\OAuth2\Server\Exception\OAuthServerException;
-
-
-/**
- * SecureKey class
- */
-class SecureKey
-{
-    /**
-     * Generate a new unique code
-     *
-     * @param integer $len Length of the generated code
-     *
-     * @return string
-     * @throws \League\OAuth2\Server\Exception\OAuthServerException
-     */
-    public static function generate($len = 40)
-    {
-        try {
-            $string = random_bytes($len);
-        } catch (\TypeError $e) {
-            // Well, it's an integer, so this IS unexpected.
-            throw OAuthServerException::serverError("An unexpected error has occurred");
-        } catch (\Error $e) {
-            // This is also unexpected because 32 is a reasonable integer.
-            throw OAuthServerException::serverError("An unexpected error has occurred");
-        } catch (\Exception $e) {
-            // If you get this message, the CSPRNG failed hard.
-            throw OAuthServerException::serverError("Could not generate a random string. Is our OS secure?");
-        }
-
-        return bin2hex($string);
-    }
-}