This book constitutes the thoroughly refereed post-proceedings of the 4th International Workshop on Cryptographic Hardware and Embedded Systems, CHES 2002, held in Redwood Shores, California, USA in August 2002. The 41 revised full papers presented together with two invited contributions were carefully selected from 101 submissions during two rounds of reviewing and revision. The papers are organized in topical sections on attack strategies, finite field and modular arithmetic, elliptic curve cryptography, AES and AES candidates, tamper resistance, RSA implementation, random number generation, new primitives, hardware for cryptanalysis.