Laravel Error Message : The only supported ciphers are AES-128-CBC and AES-256-CBC with the correct key lengths.

This is an article which is specifically discussed an error shown as the title of this article. The error is ‘The only supported ciphers are AES-128-CBC and AES-256-CBC with the correct key lengths.’ The error itself can be shown in the following image :

It is an error which is also can be found in the Laravel log file as shown below :

[2017-04-28 06:16:00] local.ERROR: RuntimeException: The only supported ciphers are AES-128-CBC and AES-256-CBC with the correct key lengths. in /var/www/html/testing/laravel-project/vendor/laravel/framework/src/Illuminate/Encryption/Encrypter.php:43
Stack trace:
#0 /var/www/html/testing/laravel-project/vendor/laravel/framework/src/Illuminate/Encryption/EncryptionServiceProvider.php(27): Illuminate\Encryption\Encrypter->__construct('Tc2EiYme62mAZwe...', 'AES-256-CBC')
#1 /var/www/html/testing/laravel-project/vendor/laravel/framework/src/Illuminate/Container/Container.php(746): Illuminate\Encryption\EncryptionServiceProvider->Illuminate\Encryption\{closure}(Object(Illuminate\Foundation\Application), Array)
#2 /var/www/html/testing/laravel-project/vendor/laravel/framework/src/Illuminate/Container/Container.php(644): Illuminate\Container\Container->build(Object(Closure), Array)
#3 /var/www/html/testing/laravel-project/vendor/laravel/framework/src/Illuminate/Foundation/Application.php(709): Illuminate\Container\Container->make('encrypter', Array)
#4 /var/www/html/testing/laravel-project/vendor/laravel/framework/src/Illuminate/Container/Container.php(864): Illuminate\Foundation\Application->make('encrypter')

The cause of the above error can be fall into the following reason :

1. The environment variables doesn’t have APP_KEY whenever the cipher defined in the app.php file located in config folder inside the root folder of web-based application using Laravel framework is set to ‘AES-128-CBC’ or ‘AES-256-CBC’. Below is the snippet code of config/app.php showing the definion of cipher field :

/*    |-----------------------------------------------------------------------
| Encryption Key    |-----------------------------------------------------------------------
|
| This key is used by the Illuminate encrypter service and should be set
| to a random, 32 character string, otherwise these encrypted strings
| will not be safe. Please do this before deploying an application!
|
*/
'key' => env('APP_KEY',''),
'cipher' => 'AES-256-CBC',

As long as the cipher is set into ‘AES-128-CBC’ or ‘AES-256-CBC’, the following field named ” which is set in file .env located in the root folder of web-application using Laravel framework.

APP_KEY=base64:8bNcWn9rjqhmSQcY6wmU2h0dr6SZx6vHCoYo6KNByqQ=

The above is an example of APP_KEY which can be generated by executing the following command from the bash prompt :

php artisan key:generate

2. The APP_KEY in the file named .env is not defined. This is actually related with the reason stated in the first option. Defining the value of APP_KEY cannot be done randomly. As shown in the information previously, it can be generated by executing ‘php artisan key:generate’ from the command prompt specifically in the root folder of web-application using Laravel framework.

After solving and confirming the above things, the page should have been previewed normally.