The Information Security Conference 2001 brought together individuals involved in multiple disciplines of information security to foster the exchange of ideas. The conference, an outgrowth of the Information Security Workshop (ISW) series, was held in Málaga, Spain, on October 1–3, 2001. Previous workshops were ISW '97 at Ishikawa, Japan; ISW '99 at Kuala Lumpur, Malaysia; and ISW 2000 at Wollongong, Australia. The General Co chairs, Javier López and Eiji Okamoto, oversaw the local organization, registration, and performed many other tasks. Many individuals deserve thanks for their contribution to the success of the conference. José M. Troya was the Conference Chair. The General Co chairs were assisted with local arrangements by Antonio Maña, Carlos Maraval, Juan J. Ortega, José M. Sierra, and Miguel Soriano. This was the first year that the conference accepted electronic submissions. Many thanks to Dawn Gibson for assisting in developing and maintaining the electronic submission servers. The conference received 98 submissions of which 37 papers were accepted for presentation. These proceedings contain revised versions of the accepted papers. Revisions were not checked and the authors bear full responsibility for the contents of their papers. The Program Committee consisted of Elisa Bertino, Università di Milano; G. R.