This book constitutes the refereed proceedings of the 12th Asian Computing Science Conference, ASIAN 2007, held in Doha, Qatar, in December 2007. Covering all current aspects of computer and network security, the papers are organized in topical sections on program security, computer security, access control, protocols, intrusion detection, network security, and safe execution.

We review the elements of the graphical user interface of traditional spreadsheet applications and describe practical methodologies for designing user interfaces borrowed from the field of cognitive psychology.