The International Workshop on Security (IWSEC 2007) was the second in the annualseriesthat startedin 2006.IWSEC 2007washeld at the New Public Hall in Nara, Japan, during October 29 31, 2007. This year there were 112 paper submissions, and from these 30 papers were accepted. Accepted papers came from 27 di?erent countries, with the largest proportion coming from Japan (12). Estonia, China, Korea, Spain, Taiwan and the USA contributed 2 papers each and Canada, Germany, Greece, Poland, Turkeyand Vietnam contributed 1 paper each. We would liketo thank all of the authors who submitted papers to...