Method subBytesDec

src/main/java/com/thealgorithms/ciphers/AES.java:2555–2563

substitutes 8-Bit long substrings of the input using the inverse S-Box for decryption and returns the result. @return subtraction Output

(BigInteger ciphertext)

     * @return subtraction Output
     */
    public static BigInteger subBytesDec(BigInteger ciphertext) {
        int[] cells = splitBlockIntoCells(ciphertext);

        for (int i = 0; i < 16; i++) {
            cells[i] = INVERSE_SBOX[cells[i]];
        }

        return mergeCellsIntoBlock(cells);
    }

    /**
     * Cell permutation step. Shifts cells within the rows of the input and