Laravel 5 Application Key
In Laravel, the application key is a unique, random string that is used to encrypt user sessions and other sensitive data. It is stored in the APP_KEY environment variable in your .env file.
To set the application key, you can use the php artisan key:generate command. This will generate a new random key and update the APP_KEY variable in your .env file with the new value. If you have an existing application and you have not set the application key, you should run this command as soon as possible to secure your application.
If you have lost the application key and you are unable to run the key:generate command, you can manually set a new key by updating the APP_KEY variable in the .env file with a new random string. Make sure to use a strong, random key to ensure the security of your application.