Laravel - Encryption - Configuration

Before using Laravel's encrypter, you must set the key configuration option in your config/app.php configuration file. This configuration value is driven by the APP_KEY environment variable. You should use the php artisan key:generate command to generate this variable's value since the key:generate command will use PHP's secure random bytes generator to build a cryptographically secure key for your application. Typically, the value of the APP_KEY environment variable will be generated for you during Laravel's installation.