This book contains the best papers of the 4th International Conference on E-business and Telecommunications (ICETE), which was held during July 28–31, 2007 in Barcelona, Spain. The conference reflects a continuing effort to increase the dissemination of recent research results among professionals who work in the areas of e-business and telecommunications. ICETE is a joint international conf- ence integrating four major areas of knowledge that are divided into four cor- sponding conferences: ICE-B (International Conference on e-Business), SECRYPT (International Conference on Security and Cryptography), WINSYS (International Conference on Wireless Information Systems) and SIGMAP (International Conf- ence on Signal Processing and Multimedia). The program of this joint conference included several outstanding keynote lectures presented by internationally renowned distinguished researchers who are experts in the various ICETE areas. Their keynote speeches contributed to the ov- all quality of the program and heightened the significance of the theme of the conference. The conference topic areas define a broad spectrum in the key areas of- business and telecommunications. This wide view has made it appealing to a global audience of engineers, scientists, business practitioners and policy experts. The papers accepted and presented at the conference demonstrated a number of new and innovative solutions for e-business and telecommunication networks and systems, showing that the technical problems in these fields are challenging, related and significant.