| 摘要 |
Provided is an encryption/decryption device using a block cipher algorithm HIGHT, which processes data of 64 bits with a block cipher HIGHT. The encryption/decryption device includes a round operation unit. The round operation unit divides 64-bit input data into a higher 32 bit and a lower 32 bit per round and performs iterative operations for 34 rounds to output a round operations result as below, wherein the 34 rounds consist of an initial round, a first to a 32^nd rounds, and a final round. During operations in the initial and final rounds, input data is cyclic-shifted by a first byte, a second byte, a third byte, and a fourth byte, wherein the input data is a 32-bit signal, and the lowest byte of the 32-bit signal is the first byte, an upper byte of the first byte is the second byte, an upper byte of the second byte is the third byte, and an upper byte of the third byte is the fourth byte. During operations in the first to 32^nd rounds, in case of encryption, cyclic shifts are carried out per byte in the lower 32 bits when the lower 32 bits are operated, and the higher 32 bits are cyclically shifted per byte together with any one operated byte of the lower 32 bits when the higher 32 bits are operated. In case of decryption, the higher 32 bits are cyclically shifted per byte in the higher 32 bits when the higher 32 bits are operated, and the lower 32 bits are cyclically shifted by byte together with any on operated byte of the higher 32 bits when the lower 32 bits are operated. |
