This book collects a selection of the papers presented at the 21st International Tyrrhenian Workshop on Digital Communications, organized by CNIT and dedicated this year to the theme "Trustworthy Internet". The workshop provided a lively discussion on the challenges involved in reshaping the Internet into a trustworthy reality, articulated around the Internet by and for People, the Internet of Contents, the Internet of Services and the Internet of Things, supported by the Network Infrastructure foundation. The papers have been revised after the workshop to take account of feedbacks received by the audience. The book also includes: i) an introduction by the Editors, setting the scene and presenting evolution scenarios; ii) five papers written by the session chairmen, reputed scientists, and each dedicated to a facet of the trustworthy Internet vision; iii) a concluding paper, reporting the outcomes of a panel held at the conclusion of the workshop, written by the two keynote speakers.

Giuseppe Bianchi has been Full Professor of Telecommunications at the School of Engineering of the University of Roma Tor Vergata since January 2007. Nicola Blefari Melazzi is Full Professor of Telecommunications at the Università di Roma ''Tor Vergataa¿?, teaching courses in Telecommunications Networks and Foundations of Internet. He has been the director of the PhD program in ''Telecommunications and Microelectronic Engineeringa¿? and has been elected director of the undergraduate (''Laureaa¿?) and graduate (''Laurea Magistralea¿?) programs in Telecommunications Engineering in November 2008. Luca Salgarelli has been teaching undergraduate and graduate courses in Networking (pages in Italian) at the University of Brescia since January 2003.