Abridging Scientific Communities Integration with a General Purpose Grid and Cloud Portal In the framework of the Italian Grid Infrastructure, we have designed a web portal which aims at providing a powerful and easy to use gateway to distributed computing resources and cloud services provisioning. We feel that one of the key point that this kind of application must be able to address is the possibility to hide the complexity of the X509 certificates management. In fact, while the PKI infrastructure is certainly one of the main aspect of the Grid environment, it is also one of the bigger obstacles that very often prevents the new users from approaching it. Through the portal users can securely run their applications without facing the complexity of the authentication infrastructure. It also interfaces with external Infrastructure as a Service (IaaS) frameworks for the dynamic provisioning of computing resources. The portal architecture is based on an external authentication layer providing strong user identification by means of an accredited identity federation. The generation of credential is handled interfacing the portal to a CA online using the OAuth protocol and saving the certificate into a MyProxy server. The portal gives full access to Grid functionalities without requiring the users to have a X.509 certificates hiding the complexities of proxy management. The portal also provides simplified access to common Grid data-management operations avoiding bottlenecks for large or many concurrent file transfers. Our data management solution consists in one or more WebDAV storage devices, external to the portal, where the users can easily upload their data from a standard desktop or laptop with every kind of operating system without requiring the installation of custom Grid software on the client side. The portal subsequently is in charge to asynchronously coping and registering the data over the Grid infrastructure hiding the Grid middleware complexity to the end user.. Primary Authors: Marco Bencivenni, Paolo Veronesi, Giuseppe Misurelli, Andrea Ceccanti, Valerio Venturi (INFN CNAF & IGI) Vincenzo Ciaschini (INFN CNAF) Luciano Gaido, Riccardo Brunetti (INFN Torino & IGI) Diego Michelotto (INFN Ferrara & INFN CNAF) Giacinto Donvito (INFN Bari & IGI)