A cryptographic device (100) calculates a block cipher (500) on a block cipher input (105) and produces a block cipher output (106). The block cipher calculation operates on encoded values (210). The cryptographic device includes a round function unit (140; 300) for applying the final round (118) of the multiple rounds of cryptographic processing implementing the block cipher. A first output unit (160) and second output unit (180) decodes encoded output data (132, 152).