Installation wampServer et laravel (Pas de réponses)

Bonsoir,
j'ai effectué toutes les étapes nécessaire pour installer wampserver et le framework laravel (à partir de ce lien [www.rbastien.com]).

Seulement, pour consulter le projet laravel à partir du navigateur j'ai eu une page indiquant ceci :

""

1/1 FatalThrowableError in Encrypter.php line 66: Fatal error: Call to undefined function openssl_encrypt()

in Encrypter.php line 66
at Encrypter->encrypt('1UO4fc0y7t8sBOnpqw8C3vezRrS9yblcrAkynNEd') in EncryptCookies.php line 131
at EncryptCookies->encrypt(object(Response)) in EncryptCookies.php line 59
at EncryptCookies->handle(object(Request), object(Closure))
at call_user_func_array(array(object(EncryptCookies), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 136
at Pipeline->Illuminate\Pipeline\{closure}(object(Request))
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 32
at Pipeline->Illuminate\Routing\{closure}(object(Request))
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 102
at Pipeline->then(object(Closure)) in Router.php line 726
at Router->runRouteWithinStack(object(Route), object(Request)) in Router.php line 699
at Router->dispatchToRoute(object(Request)) in Router.php line 675
at Router->dispatch(object(Request)) in Kernel.php line 246
at Kernel->Illuminate\Foundation\Http\{closure}(object(Request))
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 52
at Pipeline->Illuminate\Routing\{closure}(object(Request)) in CheckForMaintenanceMode.php line 44
at CheckForMaintenanceMode->handle(object(Request), object(Closure))
at call_user_func_array(array(object(CheckForMaintenanceMode), 'handle'), array(object(Request), object(Closure))) in Pipeline.php line 136
at Pipeline->Illuminate\Pipeline\{closure}(object(Request))
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 32
at Pipeline->Illuminate\Routing\{closure}(object(Request))
at call_user_func(object(Closure), object(Request)) in Pipeline.php line 102
at Pipeline->then(object(Closure)) in Kernel.php line 132
at Kernel->sendRequestThroughRouter(object(Request)) in Kernel.php line 99
at Kernel->handle(object(Request)) in index.php line 53

""
Lorsque je veux accéder à Phpmyadmin, ça m'affiche l'erreur suivante :

" The mbstring extension is missing. Please check your PHP configuration. "

Pourtant, j'ai remplacé "ext" par le path relatif au même répertoire, j'ai éliminer les ";" pour activer les extensions suivantes:

"""
extension=php_ldap.dll
extension=php_mbstring.dll
extension=php_exif.dll ; Must be after mbstring as it depends on it
extension=php_mysql.dll
extension=php_mysqli.dll
extension=php_openssl.dll

"""
et d'autres extensions.
Pour le moment je ne vois de solution pour mon problème.
J'attend vos conseils et vos interventions, merci .