.env

STRIPE_SECRET_KEY=XXXXXXX
STRIPE_PUBLIC_KEY=YYYYYYY

app.Providers.StripeServiceProvider.php

<?php namespace App\Providers;

use Illuminate\Support\ServiceProvider;
use Stripe\Stripe;
use Config;
use Blade;

class StripeServiceProvider extends ServiceProvider {

    /**
     * Indicates if loading of the provider is deferred.
     *
     * @var bool
     */
    protected $defer = false;

    /**
     * Bootstrap the application events.
     *
     * @return void
     */
    public function boot()
    {
        $api_key = Config::get('stripe.api_key');
        $public_key = Config::get('stripe.publishable_key');

        Stripe::setApiKey($api_key);

        Blade::extend(function($view, $Compiler) use ($public_key) {
            $pattern = $Compiler->createPlainMatcher('stripePublicKey');
            return preg_replace($pattern, $public_key, $view);
        });
    }

    /**
     * Register the service provider.
     *
     * @return void
     */
    public function register()
    {
        //
    }

    /**
     * Get the services provided by the provider.
     *
     * @return array
     */
    public function provides()
    {
        return array();
    }

}

config.stripe.php

<?php

return array(
	'api_key' => env('STRIPE_SECRET_KEY', ''),
	'publishable_key' => env('STRIPE_PUBLIC_KEY', ''),
);