@Article {dfpps-tcc2015,
    author = {S. {De Capitani di Vimercati} and S. Foresti and S. Paraboschi and G. Pelosi and P. Samarati},
    title = {Three-Server Swapping for Access Confidentiality},
    journal = {IEEE Transactions on Cloud Computing (TCC)},
    year = {2015},
    note = {to appear}
}