Security Protocols XVII

This book constitutes the thoroughly refereed post-proceedings of the 17th International Workshop on Security Protocols, SP 2009, held in Cambridge, UK, in April 2009. The 17 revised full papers presented together with edited transcriptions of some of the discussions following the presentations have gone through multiple rounds of reviewing, revision, and selection. The theme of this workshop was "Brief Encounters". In the old days, security protocols were typically run first as preliminaries to