Fast Software Encryption is a now eleven years old workshop on symmetric cryptography, including the design and analysis of block ciphers and stream ciphers as well as hash functions and message authentication codes. The FSE workshop was held the first time in Cambridge in 1993, followed by Leuven in 1994, Cambridge in 1996, Haifa in 1997, Paris in 1998, Rome in 1999, New York in 2000, Yokohama in 2001, Leuven in 2002, and Lund in 2003.

This Fast Software Encryption Workshop, FSE 2004, was held February 5-7, 2004 in Delhi, India. The workshop was sponsored by IACR (International Association for Cryptologic Research) and organized in cooperation with the Indian Statistical Institute, Delhi, and Cryptology Research Society of India (CRSI).

This year a total of 75 papers were submitted to FSE 2004. After a seven week reviewing process, 28 papers were accepted for presentation at the workshop. In addition, we were fortunate to have in the program two invited talks, by Adi Shamir and David Wagner.

During the workshop a rump section was held. 7 presentations were made & all the presentors were given the option of submitting it for possible inclusion in the proceedings. Only one paper was submitted which was refereed and accepted. This paper appears at the end of these proceedings.

We would like to thank the following people. First Springer Verlag for publishing the proceedings in the Lecture Notes in Computer Science. Next the submitting authors, the committee members, the external reviewers, the general co-chairs Subhamoy Maitra and R.L. Karandikar, and the local organizing committee, for their hard work. Bart Preneel for letting us use COSIC's Webreview software in the review process and Thomas Herlea for his support. We are indebted to Lund University, especially Thomas Johansson, Bijit Roy and Sugata Gangopadhyay for hosting the Webreview site. Additionally we would like to thank Partha Mukhopadhyay, Sourav Mukhopadhyay, Malapati Raja Sekhar, Chandan Biswas for handling all submissions and Madhusudan Karan for putting together the Pre-Proceedings. We also like to thank the sponsors: Infosys Technology Ltd., Honeywell Corporation and Via Technology.

The organizing committee consists in Sanjay Burman (CAIR, Bangalore), Ramendra S. Baoni (Bisecure Technologies Pvt. Ltd., Delhi), Hiranmoy Ghosh (Tata Infotech Ltd. Delhi), Abdul Sakib Mondal (Infosys Technologies Ltd., Bangalore), Arup Pal (ISI, Delhi), N.R. Pillai (SAG, Delhi), P.K.Saxena (SAG, Delhi), and Amitabha Sinha (ISI, Kolkata), who served as Treasurer. Let's thank them all.