These are the proceedings of CHES 2003, the ?fth workshop on Cryptographic HardwareandEmbeddedSystems, heldinCologneonSeptember8 10,2003.As with every previous workshop, there was a record number of submissions despite themuchearlierdeadlineinthisyear scallforpapers.Thisisaclearindication of the growing international importance of the scope of the conference and the relevance of the subject material to both industry and academia. The increasing competition for presenting at the conference has led to many excellent papers and a higher standard overall. From the 111 submissions, time...