The present invention relates to an improved white box cipher device for ARIA block ciphers, and more specifically, as a white box cipher device, a white box cipher is implemented by combining a table of operations used in ARIA block ciphers. However, in order to white box encrypt the ARIA block cipher in 32-bit units, the round function of the ARIA block cipher is changed in the order of key expansion (AddRoundKey), substitution layer (SubstLayer), and spreading layer (DiffLayer), and 16 bytes By dividing the operation of the spreading layer, which is a unit, into a first matrix (M 1 ), a second matrix (P), a first matrix (M 1 ) and a third matrix (M) that can be expressed in units of 4 bytes, the key expansion , a Type 2 table for calculating the third matrix of the permutation layer and the spreading layer, a Type 5a table for calculating the first matrix and the second matrix, and a Type 5b table for calculating the first matrix characterized. According to the improved white box cipher of the ARIA block cipher proposed in the present invention, a table in which the operations used in the ARIA block cipher are tabled is used, but the ARIA block cipher in 128-bit units is converted to a 32-bit white box cipher. In order to implement as , the operation of the spreading layer of the ARIA block cipher is divided into a first matrix, a second matrix, a first matrix and a third matrix that can be expressed in units of 4 bytes, and the third of the key expansion, substitution layer, and spreading layer By composing a Type 2 table that operates a matrix, a Type 5a table that operates the first and second matrices, and a Type 5b table that operates the first matrix, the number of XORs and the table size are reduced to whiten ARIA block ciphers more efficiently It can be implemented in a box method.
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