Patent ID: 8335313

Claim:
An encryption device including a data processing unit to convert 2n-bit data L and an exclusive OR calculator to calculate an exclusive OR of a process result of the data processing unit and 2n-bit data R comprising: a first register to store n-bit data; a first multiplexer to selectively output one of the n-bit data stored in the first register, the higher-order n bits LL of the data L and lower-order n bits LR of the data L; a first exclusive OR calculator to calculate an exclusive OR of an output of the first multiplexer and a round key KOij (j=natural number); a first data processing unit to convert an output of the first exclusive OR calculator to n-bit data, using an extended key KIik (k=natural number); a second multiplexer to selectively output one of lower-order n bits LR of the data L, n-bit “0” data and n-bit data stored in the first register; a second exclusive OR calculator to calculate an exclusive OR of an output of the second multiplexer and an output of the first data processing unit; a de-multiplexer to output an output of the second exclusive OR calculator to the first register; a third multiplexer to selectively output one of an output of the second exclusive OR calculator or a round key KOim (m=natural number); a second register to store the data R; a third exclusive OR calculator to calculate an exclusive OR of higher-order n bits RL of data R stored in the second register and an output of the third multiplexer; and a fourth exclusive OR calculator to calculate an exclusive OR of an output of the second multiplexer and lower-order n bits RR of data R stored in the second register, wherein the first multiplexer, the second multiplexer, the third multiplexer and the de-multiplexer are externally controlled, the first register inputs and stores an output of the de-multiplexer, and the second register stores an output of the third OR calculator and an output of the fourth exclusive OR calculator as higher-order n bits RL and lower-order n bits RR of data R, respectively.