Grid computing is currently shifting toward a new processing model known as business services. The use of Grid technology, in fact, allows business companies to achieve an higher productivity, to decrease maintenance costs and to adapt to market demands with an increased customer satisfaction. To meet these challenges, Grid computing needs to address several issues in term of Quality of Service, Service accountability and Security.Our work, built on Grid Security Infrastructure (GSI), provides new capabilities (i.e. a strong security data storage) to be used on top of different Grid middlewares. The solution is specifically implemented on gLite and accomplishes the access to data storage Grid resources in a uniform and transparent way. The proposed approach is based on XML data encapsulation to store encrypted data and metadata as well as data owners, X509v3 certificates, AES keys, data size, and file format.