"Cryptographic Hardware and Embedded Systems - CHES 2009" is a comprehensive collection of research papers presented at the 11th Workshop on Cryptographic Hardware and Embedded Systems. The workshop took place from September 6 to 9, 2009, in Lausanne, Switzerland, and was sponsored by the International Association for Cryptologic Research (IACR). With a record number of 148 submissions from 29 countries and an acceptance rate of only 19.6%, this work reflects the rigorous selection criteria and high quality of the submitted papers. The contributions were carefully selected and evaluated by an international program committee consisting of 53 members from various countries. The collected works provide deep insights into the latest developments and trends in the field of cryptographic engineering and are a valuable resource for professionals and researchers in this dynamic and rapidly evolving area.