It has been a real pleasure to have taken part in organizing the 12th Inter- tional Conference on Practice and Theory in Public Key Cryptography (PKC 2009). PKC 2009 was held March 18-20, 2009, on the campus of the Univ- sity of California, Irvine (UCI). As usual, it was sponsored by the International Association for Cryptologic Research (IACR) in cooperation with: - UCI Secure Computing and Networking Center (SCONCE) - UCI Donald Bren School of Information and Computer Sciences (DBSICS) - California Institute for Telecommunications and Information Technology (CalIT2) The PKC 2008 Program...