Apparatus for supporting advanced encryption standard encryption and decryption

A round module for supporting advanced encryption standard (AES) to perform encryption or decryption operation selectively on an input data code with a subkey and output an output data code, the round module comprising:

• a bitwise exclusive-OR (EX-OR) device for performing bitwise exclusive-OR (EX-OR) operation on the input data code and the subkey so as to output a first output code;
• a first multiplexer, coupled to the EX-OR device, wherein the first multiplexer, according to a selection signal, selectively outputs one of the cipher data code and the first output code as a first product code;
• a byte-substitution/inverse-byte-substitution operation (SubBytes/InvSubBytes) module, coupled to the first multiplexer, for selectively performing byte-substitution/inverse-byte-substitution operation (SubBytes/InvSubBytes) on the first output code so as to output a substitution output code, the SubBytes/InvSubBytes module comprising:
• a first matrix operation module for performing a first matrix operation on the first output code and outputting the result of the first matrix operation;
• a first exclusive-OR operation module for performing a first exclusive-OR operation on the first output code and outputting the result of the first exclusive-OR operation;
• a first selector, coupled to the first matrix operation module and the first exclusive-OR operation module, for selecting either the result of the first exclusive-OR operation or the result of the first matrix operation, according to the selection signal, as an output data code of the first selector;
• a table-lookup operation module, coupled to the first selector, for performing a table-lookup operation so as to output a table-lookup data code according to the output data code from the first selector;
• a second matrix operation module for performing a second matrix operation on the table-lookup data code and outputting the result of the second matrix operation;
• a second exclusive-OR operation module for performing a second exclusive-OR operation on the table-lookup data code and outputting the result of the second exclusive-OR operation;
• and
• a second selector, coupled to the second matrix operation module and the second exclusive-OR operation module, for selecting one of the result of the second matrix operation and the result of the second exclusive-OR operation, according to the selection signal, as the substitution output code;
• a row-shifting/inverse-row-shifting operation (ShiftRows/InvShiftRows) module, coupled to the SubBytes/InvSubBytes module, for selectively performing row-shifting/inverse-row-shifting operation (ShiftRows/InvShiftRows) on the substitution output code so as to output a shifted code;
• a second multiplexer, coupled to the EX-OR device and the ShiftRows/InvShiftRows module, wherein the second multiplexer, according to the selection signal, selectively outputs one of the first output code and the shifted code as a second product code;
• a column-mixing/inverse-column-mixing operation (MixColumns/InvMixColumns) module, coupled to the second multiplexer, for selectively performing column-mixing/inverse-column-mixing operation (MixColumns/InvMixColumns) on the second product code so as to output a mixed code;
• a third multiplexer, coupled to the second multiplexer and the MixColumns/InvMixColumns module, according to a cipher detection signal, for selectively outputting one of the second product code and the mixed code as a third product code, wherein the third product code is the cipher data code;
• a fourth multiplexer, coupled to the third multiplexer and the ShiftRows/InvShiftRows module, wherein the fourth multiplexer, according to the selection signal, selectively outputs one of the shifted code and the cipher data code as a fourth product code;
• and
• a fifth multiplexer, coupled to the fourth multiplexer and the EX-OR device, wherein the fifth multiplexer, according to a round detection signal, selectively outputs one of the fourth product code and the first output code as the output data code for the apparatus.

An apparatus for performing advanced encryption standard (AES) encryption and decryption selectively on an input data code so as to produce an output data code, the apparatus comprising:

• a round operation device for performing a round operation with respect to either encryption or decryption selectively on an input code and a subkey so as to output a round operation output code;
• a key expansion operation device, coupled to the round operation module, for generating the subkey for the round operation with respect to either encryption or decryption selectively, wherein the subkey is a desired subkey based on a given subkey;
• and
• a key storage device, coupled to the round operation device and the key expansion operation device, for subkey storage and distribution so as to enable the round operation device and the key expansion operation device to perform the round operation;
• wherein the round operation device comprises a byte-substitution/inverse-byte-substitution operation (SubBytes/InvSubBytes) module, for selectively performing byte-substitution/inverse-byte-substitution operation (SubBytes/InvSubBytes) on an operation input code which is based on the input code and subkey received by the round operation device so as to output a substitution output code, the SubBytes/InvSubBytes module comprising:
• a first matrix operation module for performing a first matrix operation on the operation input code and outputting the result of the first matrix operation;
• a first exclusive-OR operation module for performing a first exclusive-OR operation on the operation input code and outputting the result of the first exclusive-OR operation;
• a first selector, coupled to the first matrix operation module and the first exclusive-OR operation module, for selecting one from the result of the first exclusive-OR operation and the result of the first matrix operation, according to the selection signal, as an output code of the first selector;
• a table-lookup operation module, coupled to the first selector, for performing a table-lookup operation so as to output a table-lookup data code according to the output code of the first selector;
• a second matrix operation module for performing a second matrix operation on the table-lookup data code and outputting the result of the second matrix operation;
• a second exclusive-OR operation module for performing a second exclusive-OR operation on the table-lookup data code and outputting the result of the second exclusive-OR operation;
• and
• a second selector, coupled to the second matrix operation module and the second exclusive-OR operation module, for selecting one from the result of the second matrix operation and the result of the second exclusive-OR operation, according to the selection signal, as the substitution output code;
• wherein the key storage device receives the round operation output code and receives the subkey from the key expansion operation device;
• the key storage device outputs the given subkey to the key expansion operation device and outputs the input code to the round operation device;
• the key storage device buffers the input data code, performs subkey storage and distribution, receives the round operation output code and the subkey generated by the key expansion operation device, and outputs the output data code.