ThesearetheproceedingsofCHES2002,theFourthWorkshoponCryptographic Hardware and Embedded Systems. After the ?rst two CHES Workshops held in Massachusetts, and the third held in Europe, this is the ?rst Workshop on the West Coast of the United States. There was a record number of submissions this year and in response the technical program was extended to 3 days. As is evident by the papers in these proceedings, there have been again many excellent submissions. Selecting the papers for this year’s CHES was not an easy task, and we regret that we could not accept many contributions due to the limited availability of time. There were 101 submissions this year, of which 39 were selected for presentation. We continue to observe a steady increase over previous years: 42 submissions at CHES ’99, 51 at CHES 2000, and 66 at CHES 2001. We interpret this as a continuing need for a workshop series that c- bines theory and practice for integrating strong security features into modern communicationsandcomputerapplications. Inadditiontothesubmittedcont- butions, Jean-Jacques Quisquater (UCL, Belgium), Sanjay Sarma (MIT, USA) and a panel of experts on hardware random number generation gave invited talks. As in the previous years, the focus of the Workshop is on all aspects of cr- tographic hardware and embedded system security. Of special interest were c- tributionsthatdescribenewmethodsfore?cienthardwareimplementationsand high-speed software for embedded systems, e. g. , smart cards, microprocessors, DSPs, etc. CHES also continues to be an important forum for new theoretical and practical ?ndings in the important and growing ?eld of side-channel attacks.

Table of Contents:
Invited Talk.- CHES: Past, Present, and Future.- Attack Strategies.- Optical Fault Induction Attacks.- Template Attacks.- The EM Side—Channel(s).- Finite Field and Modular Arithmetic I.- Enhanced Montgomery Multiplication.- New Algorithm for Classical Modular Inverse.- Increasing the Bitlength of a Crypto-Coprocessor.- Elliptic Curve Cryptography I.- Enhancing Simple Power-Analysis Attacks on Elliptic Curve Cryptosystems.- Implementation of Elliptic Curve Cryptography with Built-In Counter Measures against Side Channel Attacks.- Secure Elliptic Curve Implementations: An Analysis of Resistance to Power-Attacks in a DSP Processor.- Address-Bit Differential Power Analysis of Cryptographic Schemes OK-ECDH and OK-ECDSA.- AES and AES Candidates.- 2Gbit/s Hardware Realizations of RIJNDAEL and SERPENT: A Comparative Analysis.- Efficient Software Implementation of AES on 32-Bit Platforms.- An Optimized S-Box Circuit Architecture for Low Power AES Design.- Simplified Adaptive Multiplicative Masking for AES.- Multiplicative Masking and Power Analysis of AES.- Tamper Resistance.- Keeping Secrets in Hardware: The Microsoft XboxTM Case Study.- RSA Implementation.- A DPA Attack against the Modular Reduction within a CRT Implementation of RSA.- Further Results and Considerations on Side Channel Attacks on RSA.- Fault Attacks on RSA with CRT: Concrete Results and Practical Countermeasures.- Finite Field and Modular Arithmetic II.- Some Security Aspects of the MIST Randomized Exponentiation Algorithm.- The Montgomery Powering Ladder.- DPA Countermeasures by Improving the Window Method.- Efficient Subgroup Exponentiation in Quadratic and Sixth Degree Extensions.- Elliptic Curve Cryptography II.- On the Efficient Generation of Elliptic Curves over Prime Fields.- An End-to-End SystemsApproach to Elliptic Curve Cryptography.- A Low-Power Design for an Elliptic Curve Digital Signature Chip.- A Reconfigurable System on Chip Implementation for Elliptic Curve Cryptography over .- Genus Two Hyperelliptic Curve Coprocessor.- Random Number Generation.- True Random Number Generator Embedded in Reconfigurable Hardware.- Evaluation Criteria for True (Physical) Random Number Generators Used in Cryptographic Applications.- A Hardware Random Number Generator.- Invited Talk.- RFID Systems and Security and Privacy Implications.- New Primitives.- A New Class of Invertible Mappings.- Finite Field and Modular Arithmetic II.- Scalable and Unified Hardware to Compute Montgomery Inverse in GF(p) and GF(2n).- Dual-Field Arithmetic Unit for GF(p) and GF(2m).- Error Detection in Polynomial Basis Multipliers over Binary Extension Fields.- Hardware Implementation of Finite Fields of Characteristic Three.- Elliptic Curve Cryptography III.- Preventing Differential Analysis in GLV Elliptic Curve Scalar Multiplication.- Randomized Signed-Scalar Multiplication of ECC to Resist Power Attacks.- Fast Multi-scalar Multiplication Methods on Elliptic Curves with Precomputation Strategy Using Montgomery Trick.- Hardware for Cryptanalysis.- Experience Using a Low-Cost FPGA Design to Crack DES Keys.- A Time-Memory Tradeo. Using Distinguished Points: New Analysis & FPGA Results.