This workshop is intended to be a less formal counterpart to the Principles of Security and Trust (POST) conference at ETAPS, and with an emphasis on "hot topics", both of security and of its theoretical foundations and analysis. Like POST, the themes are theory of computer security; formal specification, analysis and design of security systems; automated reasoning for security analysis. Submissions about new and emerging topics (for example, those that have not appeared prominently in conferences and workshops until now) are particularly encouraged. Submissions of preliminary, tentative work are also encouraged. There is no page limit, but the length of your submission should be appropriate to its content. There will be no formal proceedings. Inclusion in informal proceedings is optional. Mark Ryan (University of Birmingham, UK) Submission: 7 January 2013 Notification: 1 February 2013 Final version for informal proceedings (optional): 22 February 2013 Dates: Saturday March 23rd, 2013