Elliptic Curve Cryptosystems (ECC) allow for shorter operand lengths compared to other public-key cryptosystems and are thus attractive for use in many security applications, especially for embedded devices. We report some very promising experimental results showing that very simple instruction set architecture extensions improve the efficiency of elliptic curve cryptography over binary finite fields in terms of execution time. We analyzed the effects of such extensions with different implementations of finite field arithmetic and elliptic curve operations, which can be used as a guideline...