With the rapid technological development of information technology, computer systems and especially embedded systems are becoming more mobile and ub- uitous. Ensuring the security of these complex and yet resource-constraineds- temshasemergedasoneofthemostpressingchallengesforresearchers.Although there are a number of information security conferences that look at particular aspects of the challenge, we decided to create the Workshop in Information - curity Theory and Practices (WISTP) to consider the problem as a whole. In additiontheworkshopaimsto bringtogetherresearchersandpractitionersin- lated disciplines and encourage interchange and practical co-operation between academia and industry. Although this is the ?rst ever WISTP event, the response from researchers wassuperbwithover68paperssubmittedforpotentialinclusionintheworkshop and proceedings. The submissions were reviewed by at least three reviewers, in most cases by four, and for program committee (PC) papers at least ?ve reviewers. This long and rigorous process was only possible thanks to the hard work of the PC members and additional reviewers, listed in the following pages. We would like to express our gratitude to the PC members, who were very supportive from the very beginning of this project. Thanks are also due to the additional expert reviewers who helped the PC to select the ?nal 20 workshop papers for publication in the proceedings. Of course we highly appreciate the e?orts of all the authors who submitted papers to WISTP 2007. We hope they will contribute again to a future edition and encourage others to do so.