Random RuntimeException: The only supported ciphers are AES-128-CBC and AES-256-CBC with the correct key length

I have same problem with Laravel 5.3 (on windows server). I did all possible attempts: checked .env file, config, artisan new key generation, cache: clear, config: clear, composer update, but the problem randomly persists.

Note that the same code with exactly same version of apache, mysql, php, doesn't generate this problem on Mac OS.

I found that the key (first parameter of Encrypter constractor) arrives "sometimes" empty and of course it fails. Most of the times the key is correct, but randomly the key arrives empty from EncryptionServiceProvider that in turns asks it to the app config.

So the only solution that worked for me was to add an if ($key) in EncryptionServiceProvider so that the Encryption constructor doesn't get called with empty key.

Of course is not a "clean" solution nor it explains the problem, but at least avoids to find the log file filled with the error:

RuntimeException: The only supported ciphers are AES-128-CBC and AES-256-CBC and pages are displayed correctly.

If this is a Laravel bug I don't know, but of course if someone could explain this I will be more then happy to know.

Below is my modified class: I just added the if ($key) line before new Encrypter:

class EncryptionServiceProvider extends ServiceProvider
{
    /**
     * Register the service provider.
     *
     * @return void
     */
    public function register()
    {
        $this->app->singleton('encrypter', function ($app) {
            $config = $app->make('config')->get('app');

            // If the key starts with "base64:", we will need to decode the key before handing
            // it off to the encrypter. Keys may be base-64 encoded for presentation and we
            // want to make sure to convert them back to the raw bytes before encrypting.
            if (Str::startsWith($key = $config['key'], 'base64:')) {
                $key = base64_decode(substr($key, 7));
            }
        if ($key)
            return new Encrypter($key, $config['cipher']);
        });
    }
}

Further details and backtrace log:

Of course, as I wrote I checked, .env file, config, artisan new key generation, cache: clear, config: clear, composer update. This stuff is ok since it works 99% of the time but randomly I get the error.

Here the back trace:

[2017-01-09 10:25:40] test.ERROR: RuntimeException: The only supported ciphers are AES-128-CBC and AES-256-CBC with the correct key lengths. in C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Encryption\Encrypter.php:43

Stack trace:

#0 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Encryption\EncryptionServiceProvider.php(27): Illuminate\Encryption\Encrypter->__construct('', 'AES-256-CBC')
#1 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Container\Container.php(746): Illuminate\Encryption\EncryptionServiceProvider->Illuminate\Encryption\{closure}(Object(Illuminate\Foundation\Application), Array)
#2 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Container\Container.php(644): Illuminate\Container\Container->build(Object(Closure), Array)
#3 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Foundation\Application.php(709): Illuminate\Container\Container->make('encrypter', Array)
#4 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Container\Container.php(864): Illuminate\Foundation\Application->make('encrypter')
#5 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Container\Container.php(819): Illuminate\Container\Container->resolveClass(Object(ReflectionParameter))
#6 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Container\Container.php(788): Illuminate\Container\Container->getDependencies(Array, Array)
#7 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Container\Container.php(644): Illuminate\Container\Container->build('App\\Http\\Middle...', Array)
#8 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Foundation\Application.php(709): Illuminate\Container\Container->make('App\\Http\\Middle...', Array)
#9 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Pipeline\Pipeline.php(127): Illuminate\Foundation\Application->make('App\\Http\\Middle...')
#10 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Routing\Pipeline.php(33): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#11 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\View\Middleware\ShareErrorsFromSession.php(49): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#12 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Pipeline\Pipeline.php(137): Illuminate\View\Middleware\ShareErrorsFromSession->handle(Object(Illuminate\Http\Request), Object(Closure))
#13 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Routing\Pipeline.php(33): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#14 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Session\Middleware\StartSession.php(64): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#15 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Pipeline\Pipeline.php(137): Illuminate\Session\Middleware\StartSession->handle(Object(Illuminate\Http\Request), Object(Closure))
#16 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Routing\Pipeline.php(33): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#17 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse.php(37): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#18 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Pipeline\Pipeline.php(137): Illuminate\Cookie\Middleware\AddQueuedCookiesToResponse->handle(Object(Illuminate\Http\Request), Object(Closure))
#19 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Routing\Pipeline.php(33): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#20 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Pipeline\Pipeline.php(104): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#21 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Routing\Router.php(655): Illuminate\Pipeline\Pipeline->then(Object(Closure))
#22 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Routing\Router.php(629): Illuminate\Routing\Router->runRouteWithinStack(Object(Illuminate\Routing\Route), Object(Illuminate\Http\Request))
#23 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Routing\Router.php(607): Illuminate\Routing\Router->dispatchToRoute(Object(Illuminate\Http\Request))
#24 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Foundation\Http\Kernel.php(268): Illuminate\Routing\Router->dispatch(Object(Illuminate\Http\Request))
#25 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Routing\Pipeline.php(53): Illuminate\Foundation\Http\Kernel->Illuminate\Foundation\Http\{closure}(Object(Illuminate\Http\Request))
#26 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode.php(46): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#27 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Pipeline\Pipeline.php(137): Illuminate\Foundation\Http\Middleware\CheckForMaintenanceMode->handle(Object(Illuminate\Http\Request), Object(Closure))
#28 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Routing\Pipeline.php(33): Illuminate\Pipeline\Pipeline->Illuminate\Pipeline\{closure}(Object(Illuminate\Http\Request))
#29 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Pipeline\Pipeline.php(104): Illuminate\Routing\Pipeline->Illuminate\Routing\{closure}(Object(Illuminate\Http\Request))
#30 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Foundation\Http\Kernel.php(150): Illuminate\Pipeline\Pipeline->then(Object(Closure))
#31 C:\Apache24\htdocs\sph\vendor\laravel\framework\src\Illuminate\Foundation\Http\Kernel.php(117): Illuminate\Foundation\Http\Kernel->sendRequestThroughRouter(Object(Illuminate\Http\Request))
#32 C:\Apache24\htdocs\sph\public\index.php(53): Illuminate\Foundation\Http\Kernel->handle(Object(Illuminate\Http\Request))
#33 {main}