This book constitutes the thoroughly refereed post-proceedings of the First International Workshop on Secure Mobile Ad-hoc Networks and Sensors, MADNES 2005, held in Singapore, in September 2005.

The 12 revised full papers presented together with 5 keynote papers and 1 invited paper were carefully reviewed and selected from a total of 33 submissions. The papers address current topics of all security aspects of constrained network environments with special focus to mobile agents, sensor networks and radio frequency (RF) devices.