AES.java

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class AES {

    public AES() {
    }

	// this is the sbox table by which we substitute blocks in our states
    public static final int[][] subTable = {{0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76}, {0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0}, {0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15}, {0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75}, {0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84}, {0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf}, {0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8}, {0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2}, {0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73}, {0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb}, {0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79}, {0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08}, {0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a}, {0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e}, {0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf}, {0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16}};
	
	// inverted value of subTable matrix
    public static final int[][] invSubTable = {{0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb}, {0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb}, {0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e}, {0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25}, {0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92}, {0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84}, {0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06}, {0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b}, {0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73}, {0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e}, {0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b}, {0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4}, {0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f}, {0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef}, {0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61}, {0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d}};
	
	// rcon table is used to calculate all values on the round key matrix
	public static final int[] rcon = {0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb};
	
	// used in mix columns step
	public static final int[][] galois = {{0x02, 0x03, 0x01, 0x01},
        {0x01, 0x02, 0x03, 0x01},
        {0x01, 0x01, 0x02, 0x03},
        {0x03, 0x01, 0x01, 0x02}};
	
    // used in inverted mix columns step
    public static final int[][] invgalois = {{0x0e, 0x0b, 0x0d, 0x09},
        {0x09, 0x0e, 0x0b, 0x0d},
        {0x0d, 0x09, 0x0e, 0x0b},
        {0x0b, 0x0d, 0x09, 0x0e}};
	

    public static void main(String args[]) throws IOException {
		
		// mode is "e" or "d" 
        String mode = args[0];
        String keyFileDir = args[1];
        String inputFileDir = args[2];

        //System.out.println(mode);
        //System.out.println(keyFileDir);
        //System.out.println(inputFileDir);
		
		// evaluate key 32 hex-characters
        BufferedReader keyreader = new BufferedReader(new FileReader(keyFileDir));
        String key = keyreader.readLine();

        BufferedReader input = new BufferedReader(new FileReader( inputFileDir ));

        AES aes = new AES();
		
		// encrypting
        if (mode.equalsIgnoreCase("e"))
        {
			// output file is defined
            FileWriter out = new FileWriter(inputFileDir + ".enc");
            String line = input.readLine();
			
			// state is actually each line, but converted into a 
			// 4x4 matrix of 2 hexadecimal characters on each 
			// cell and will be updated at each step
            int[][] state = new int[4][4];
			
			// keymatrix is a 4x44, 4x52 or 4x60 matrix that includes round keys as 4x4 matrices (depending on 128-192-256 bits of key string)
            int[][] keymatrix = aes.keySchedule(key);
			
			// processing each line in the input file
            while (line != null) {
				
                // checks should be better here, uppercase, lowercase?
                if (line.toUpperCase().matches("[0-9A-F]+"))
                {
                    
					// state is reinitialized using the next line
                    state = new int[4][4];
                    for (int i = 0; i < 4; i++)
                    {
                        for (int j = 0; j < 4; j++) {
                            state[j][i] = Integer.parseInt(line.substring((8 * i) + (2 * j), (8 * i) + (2 * j + 2)), 16);
                        }
                    }
					
					// the first round key is added to the state
					System.out.print(MatrixToString(state) + "\n");
					aes.addRoundKey(state, aes.subKey(keymatrix, 0));
					
					// assuming that key string is 128 bit, so the steps below are repeated 9 times
					System.out.print(MatrixToString(state) + "\n");
                    for (int i = 1; i < 10; i++) {
                        aes.subBytes(state);
						System.out.print(MatrixToString(state) + "\n");
                        aes.shiftRows(state);
						System.out.print(MatrixToString(state) + "\n");
                        aes.mixColumns(state, true);
						System.out.print(MatrixToString(state) + "\n");
                        aes.addRoundKey(state, aes.subKey(keymatrix, i));
						System.out.print(MatrixToString(state) + "\n");
                    }
					
					// on the last step, columns are not being mixed
                    aes.subBytes(state);
					System.out.print(MatrixToString(state) + "\n");
                    aes.shiftRows(state);
					System.out.print(MatrixToString(state) + "\n");
                    aes.addRoundKey(state, aes.subKey(keymatrix, 10));
					System.out.print(MatrixToString(state) + "\n");
					
					// convert state to a string and print it to the output file
					out.write(MatrixToString(state) + "\n");
                    line = input.readLine();
                }
				// if the line has non-hexadecimal characters, skip that line
                else
                {
                    line = input.readLine();
                }
            }
            input.close();
            out.close();
        }
		
		// decrypting - steps are almost same
        else if (args[0].equalsIgnoreCase("d"))
        {
			FileWriter out = new FileWriter(inputFileDir + ".dec");
            String line = input.readLine();
            int[][] state = new int[4][4];
			int[][] keymatrix = aes.keySchedule(key);

            while (line != null) {
                if (line.toUpperCase().matches("[0-9A-F]+"))
                {

                    state = new int[4][4];
                    for (int i = 0; i < 4; i++)
                    {
                        for (int j = 0; j < 4; j++) {
                            state[j][i] = Integer.parseInt(line.substring((8 * i) + (2 * j), (8 * i) + (2 * j + 2)), 16);
                        }
                    }
					
					// iterating backwards on the key matrix due to decryption
					System.out.print(MatrixToString(state) + "\n");
					aes.addRoundKey(state, aes.subKey(keymatrix, 10));

                    for (int i = 9; i > 0; i--) {
                        aes.invShiftRows(state);
						System.out.print(MatrixToString(state) + "\n");
                        aes.inverseSubBytes(state);
						System.out.print(MatrixToString(state) + "\n");
                        aes.addRoundKey(state, aes.subKey(keymatrix, i));
						System.out.print(MatrixToString(state) + "\n");
                        aes.mixColumns(state, false);
						System.out.print(MatrixToString(state) + "\n");
                    }
                    aes.invShiftRows(state);
					System.out.print(MatrixToString(state) + "\n");
                    aes.inverseSubBytes(state);
					System.out.print(MatrixToString(state) + "\n");
                    aes.addRoundKey(state, aes.subKey(keymatrix, 0));
					System.out.print(MatrixToString(state) + "\n");
					
					out.write(MatrixToString(state) + "\n");
                    line = input.readLine();
                }
                else
                {
                    line = input.readLine();
                }
            }
            input.close();
            out.close();
			
        }
    }
	
	// using arithmetic operations on a matrix to convert it to a single string
	public static String MatrixToString(int[][] m) 
    {
        String t = "";
        for (int i = 0; i < m.length; i++) {
            for (int j = 0; j < m[0].length; j++) {
                String h = Integer.toHexString(m[j][i]).toUpperCase();
                if (h.length() == 1) {
                    t += '0' + h;
                } else {
                    t += h;
                }
            }
        }
        return t;
    }
	
	// get the 4x4 sub-keymatrix from the original key matrix
	private int[][] subKey(int[][] km, int begin) {
        int[][] arr = new int[4][4];
        for (int i = 0; i < arr.length; i++) {
            for (int j = 0; j < arr.length; j++) {
                arr[i][j] = km[i][4 * begin + j];
            }
        }
        return arr;
    }
	
	// left-shift the rows of a state matrix by 0-1-2-3 cells
	public void shiftRows(int[][] arr) {
        for (int i = 1; i < arr.length; i++) {
            arr[i] = leftrotate(arr[i], i);
        }
    }
	
	// inverted version
	public void invShiftRows(int[][] arr) {
        for (int i = 1; i < arr.length; i++) {
            arr[i] = rightrotate(arr[i], i);
        }
    }
	
	// using subTable, update state matrix by substitute the specific cells
    public void subBytes(int[][] arr) {
        for (int i = 0; i < arr.length; i++)
        {
            for (int j = 0; j < arr[0].length; j++) {
                int temp = arr[j][i];
                arr[j][i] = subTable[temp / 16][temp % 16];
            }
        }
    }
	
	// inverted version
    public void inverseSubBytes(int[][] arr) {
        for (int i = 0; i < arr.length; i++)
        {
            for (int j = 0; j < arr[0].length; j++) {
                int temp = arr[j][i];
                arr[j][i] = invSubTable[temp / 16][temp % 16];
            }
        }
    }
    
	// these tables are used on column mix step 
	//
	// on wikipedia https://en.wikipedia.org/wiki/Rijndael_MixColumns#Galois_Multiplication_lookup_tables :
	// "Commonly, rather than implementing Galois multiplication, Rijndael implementations simply use pre-calculated lookup tables to perform the byte multiplication by 2, 3, 9, 11, 13, and 14."
    public static int[][] mul_2 ={{0x00, 0x02, 0x04, 0x06, 0x08, 0x0a, 0x0c, 0x0e, 0x10, 0x12, 0x14, 0x16, 0x18, 0x1a, 0x1c, 0x1e},
                                            {0x20, 0x22, 0x24, 0x26, 0x28, 0x2a, 0x2c, 0x2e, 0x30, 0x32, 0x34, 0x36, 0x38, 0x3a, 0x3c, 0x3e},
                                            {0x40, 0x42, 0x44, 0x46, 0x48, 0x4a, 0x4c, 0x4e, 0x50, 0x52, 0x54, 0x56, 0x58, 0x5a, 0x5c, 0x5e},
                                            {0x60, 0x62, 0x64, 0x66, 0x68, 0x6a, 0x6c, 0x6e, 0x70, 0x72, 0x74, 0x76, 0x78, 0x7a, 0x7c, 0x7e},
                                            {0x80, 0x82, 0x84, 0x86, 0x88, 0x8a, 0x8c, 0x8e, 0x90, 0x92, 0x94, 0x96, 0x98, 0x9a, 0x9c, 0x9e},
                                            {0xa0, 0xa2, 0xa4, 0xa6, 0xa8, 0xaa, 0xac, 0xae, 0xb0, 0xb2, 0xb4, 0xb6, 0xb8, 0xba, 0xbc, 0xbe},
                                            {0xc0, 0xc2, 0xc4, 0xc6, 0xc8, 0xca, 0xcc, 0xce, 0xd0, 0xd2, 0xd4, 0xd6, 0xd8, 0xda, 0xdc, 0xde},
                                            {0xe0, 0xe2, 0xe4, 0xe6, 0xe8, 0xea, 0xec, 0xee, 0xf0, 0xf2, 0xf4, 0xf6, 0xf8, 0xfa, 0xfc, 0xfe},
                                            {0x1b, 0x19, 0x1f, 0x1d, 0x13, 0x11, 0x17, 0x15, 0x0b, 0x09, 0x0f, 0x0d, 0x03, 0x01, 0x07, 0x05},
                                            {0x3b, 0x39, 0x3f, 0x3d, 0x33, 0x31, 0x37, 0x35, 0x2b, 0x29, 0x2f, 0x2d, 0x23, 0x21, 0x27, 0x25},
                                            {0x5b, 0x59, 0x5f, 0x5d, 0x53, 0x51, 0x57, 0x55, 0x4b, 0x49, 0x4f, 0x4d, 0x43, 0x41, 0x47, 0x45},
                                            {0x7b, 0x79, 0x7f, 0x7d, 0x73, 0x71, 0x77, 0x75, 0x6b, 0x69, 0x6f, 0x6d, 0x63, 0x61, 0x67, 0x65},
                                            {0x9b, 0x99, 0x9f, 0x9d, 0x93, 0x91, 0x97, 0x95, 0x8b, 0x89, 0x8f, 0x8d, 0x83, 0x81, 0x87, 0x85},
                                            {0xbb, 0xb9, 0xbf, 0xbd, 0xb3, 0xb1, 0xb7, 0xb5, 0xab, 0xa9, 0xaf, 0xad, 0xa3, 0xa1, 0xa7, 0xa5},
                                            {0xdb, 0xd9, 0xdf, 0xdd, 0xd3, 0xd1, 0xd7, 0xd5, 0xcb, 0xc9, 0xcf, 0xcd, 0xc3, 0xc1, 0xc7, 0xc5},
                                            {0xfb, 0xf9, 0xff, 0xfd, 0xf3, 0xf1, 0xf7, 0xf5, 0xeb, 0xe9, 0xef, 0xed, 0xe3, 0xe1, 0xe7, 0xe5}};

    public static int[][] mul_3 ={   {0x00,0x03,0x06,0x05,0x0c,0x0f,0x0a,0x09,0x18,0x1b,0x1e,0x1d,0x14,0x17,0x12,0x11},
                                                {0x30,0x33,0x36,0x35,0x3c,0x3f,0x3a,0x39,0x28,0x2b,0x2e,0x2d,0x24,0x27,0x22,0x21},
                                                {0x60,0x63,0x66,0x65,0x6c,0x6f,0x6a,0x69,0x78,0x7b,0x7e,0x7d,0x74,0x77,0x72,0x71},
                                                {0x50,0x53,0x56,0x55,0x5c,0x5f,0x5a,0x59,0x48,0x4b,0x4e,0x4d,0x44,0x47,0x42,0x41},
                                                {0xc0,0xc3,0xc6,0xc5,0xcc,0xcf,0xca,0xc9,0xd8,0xdb,0xde,0xdd,0xd4,0xd7,0xd2,0xd1},
                                                {0xf0,0xf3,0xf6,0xf5,0xfc,0xff,0xfa,0xf9,0xe8,0xeb,0xee,0xed,0xe4,0xe7,0xe2,0xe1},
                                                {0xa0,0xa3,0xa6,0xa5,0xac,0xaf,0xaa,0xa9,0xb8,0xbb,0xbe,0xbd,0xb4,0xb7,0xb2,0xb1},
                                                {0x90,0x93,0x96,0x95,0x9c,0x9f,0x9a,0x99,0x88,0x8b,0x8e,0x8d,0x84,0x87,0x82,0x81},
                                                {0x9b,0x98,0x9d,0x9e,0x97,0x94,0x91,0x92,0x83,0x80,0x85,0x86,0x8f,0x8c,0x89,0x8a},
                                                {0xab,0xa8,0xad,0xae,0xa7,0xa4,0xa1,0xa2,0xb3,0xb0,0xb5,0xb6,0xbf,0xbc,0xb9,0xba},
                                                {0xfb,0xf8,0xfd,0xfe,0xf7,0xf4,0xf1,0xf2,0xe3,0xe0,0xe5,0xe6,0xef,0xec,0xe9,0xea},
                                                {0xcb,0xc8,0xcd,0xce,0xc7,0xc4,0xc1,0xc2,0xd3,0xd0,0xd5,0xd6,0xdf,0xdc,0xd9,0xda},
                                                {0x5b,0x58,0x5d,0x5e,0x57,0x54,0x51,0x52,0x43,0x40,0x45,0x46,0x4f,0x4c,0x49,0x4a},
                                                {0x6b,0x68,0x6d,0x6e,0x67,0x64,0x61,0x62,0x73,0x70,0x75,0x76,0x7f,0x7c,0x79,0x7a},
                                                {0x3b,0x38,0x3d,0x3e,0x37,0x34,0x31,0x32,0x23,0x20,0x25,0x26,0x2f,0x2c,0x29,0x2a},
                                                {0x0b,0x08,0x0d,0x0e,0x07,0x04,0x01,0x02,0x13,0x10,0x15,0x16,0x1f,0x1c,0x19,0x1a}   };

    public static int[][] mul_9 = {   {0x00,0x09,0x12,0x1b,0x24,0x2d,0x36,0x3f,0x48,0x41,0x5a,0x53,0x6c,0x65,0x7e,0x77},
                                    {0x90,0x99,0x82,0x8b,0xb4,0xbd,0xa6,0xaf,0xd8,0xd1,0xca,0xc3,0xfc,0xf5,0xee,0xe7},
                                    {0x3b,0x32,0x29,0x20,0x1f,0x16,0x0d,0x04,0x73,0x7a,0x61,0x68,0x57,0x5e,0x45,0x4c},
                                    {0xab,0xa2,0xb9,0xb0,0x8f,0x86,0x9d,0x94,0xe3,0xea,0xf1,0xf8,0xc7,0xce,0xd5,0xdc},
                                    {0x76,0x7f,0x64,0x6d,0x52,0x5b,0x40,0x49,0x3e,0x37,0x2c,0x25,0x1a,0x13,0x08,0x01},
                                    {0xe6,0xef,0xf4,0xfd,0xc2,0xcb,0xd0,0xd9,0xae,0xa7,0xbc,0xb5,0x8a,0x83,0x98,0x91},
                                    {0x4d,0x44,0x5f,0x56,0x69,0x60,0x7b,0x72,0x05,0x0c,0x17,0x1e,0x21,0x28,0x33,0x3a},
                                    {0xdd,0xd4,0xcf,0xc6,0xf9,0xf0,0xeb,0xe2,0x95,0x9c,0x87,0x8e,0xb1,0xb8,0xa3,0xaa},
                                    {0xec,0xe5,0xfe,0xf7,0xc8,0xc1,0xda,0xd3,0xa4,0xad,0xb6,0xbf,0x80,0x89,0x92,0x9b},
                                    {0x7c,0x75,0x6e,0x67,0x58,0x51,0x4a,0x43,0x34,0x3d,0x26,0x2f,0x10,0x19,0x02,0x0b},
                                    {0xd7,0xde,0xc5,0xcc,0xf3,0xfa,0xe1,0xe8,0x9f,0x96,0x8d,0x84,0xbb,0xb2,0xa9,0xa0},
                                    {0x47,0x4e,0x55,0x5c,0x63,0x6a,0x71,0x78,0x0f,0x06,0x1d,0x14,0x2b,0x22,0x39,0x30},
                                    {0x9a,0x93,0x88,0x81,0xbe,0xb7,0xac,0xa5,0xd2,0xdb,0xc0,0xc9,0xf6,0xff,0xe4,0xed},
                                    {0x0a,0x03,0x18,0x11,0x2e,0x27,0x3c,0x35,0x42,0x4b,0x50,0x59,0x66,0x6f,0x74,0x7d},
                                    {0xa1,0xa8,0xb3,0xba,0x85,0x8c,0x97,0x9e,0xe9,0xe0,0xfb,0xf2,0xcd,0xc4,0xdf,0xd6},
                                    {0x31,0x38,0x23,0x2a,0x15,0x1c,0x07,0x0e,0x79,0x70,0x6b,0x62,0x5d,0x54,0x4f,0x46}   };
    
    public static int[][] mul_11 = {  {0x00,0x0b,0x16,0x1d,0x2c,0x27,0x3a,0x31,0x58,0x53,0x4e,0x45,0x74,0x7f,0x62,0x69},
                                    {0xb0,0xbb,0xa6,0xad,0x9c,0x97,0x8a,0x81,0xe8,0xe3,0xfe,0xf5,0xc4,0xcf,0xd2,0xd9},
                                    {0x7b, 0x70, 0x6d, 0x66, 0x57, 0x5c, 0x41, 0x4a, 0x23, 0x28, 0x35, 0x3e, 0x0f, 0x04, 0x19, 0x12},
                                    {0xcb,0xc0,0xdd,0xd6,0xe7,0xec,0xf1,0xfa,0x93,0x98,0x85,0x8e,0xbf,0xb4,0xa9,0xa2},
                                    {0xf6,0xfd,0xe0,0xeb,0xda,0xd1,0xcc,0xc7,0xae,0xa5,0xb8,0xb3,0x82,0x89,0x94,0x9f},
                                    {0x46,0x4d,0x50,0x5b,0x6a,0x61,0x7c,0x77,0x1e,0x15,0x08,0x03,0x32,0x39,0x24,0x2f},
                                    {0x8d,0x86,0x9b,0x90,0xa1,0xaa,0xb7,0xbc,0xd5,0xde,0xc3,0xc8,0xf9,0xf2,0xef,0xe4},
                                    {0x3d,0x36,0x2b,0x20,0x11,0x1a,0x07,0x0c,0x65,0x6e,0x73,0x78,0x49,0x42,0x5f,0x54},
                                    {0xf7,0xfc,0xe1,0xea,0xdb,0xd0,0xcd,0xc6,0xaf,0xa4,0xb9,0xb2,0x83,0x88,0x95,0x9e},
                                    {0x47,0x4c,0x51,0x5a,0x6b,0x60,0x7d,0x76,0x1f,0x14,0x09,0x02,0x33,0x38,0x25,0x2e},
                                    {0x8c,0x87,0x9a,0x91,0xa0,0xab,0xb6,0xbd,0xd4,0xdf,0xc2,0xc9,0xf8,0xf3,0xee,0xe5},
                                    {0x3c,0x37,0x2a,0x21,0x10,0x1b,0x06,0x0d,0x64,0x6f,0x72,0x79,0x48,0x43,0x5e,0x55},
                                    {0x01,0x0a,0x17,0x1c,0x2d,0x26,0x3b,0x30,0x59,0x52,0x4f,0x44,0x75,0x7e,0x63,0x68},
                                    {0xb1,0xba,0xa7,0xac,0x9d,0x96,0x8b,0x80,0xe9,0xe2,0xff,0xf4,0xc5,0xce,0xd3,0xd8},
                                    {0x7a,0x71,0x6c,0x67,0x56,0x5d,0x40,0x4b,0x22,0x29,0x34,0x3f,0x0e,0x05,0x18,0x13},
                                    {0xca,0xc1,0xdc,0xd7,0xe6,0xed,0xf0,0xfb,0x92,0x99,0x84,0x8f,0xbe,0xb5,0xa8,0xa3}   };
    
    public static int[][] mul_13 = {  {0x00,0x0d,0x1a,0x17,0x34,0x39,0x2e,0x23,0x68,0x65,0x72,0x7f,0x5c,0x51,0x46,0x4b},
                                    {0xd0,0xdd,0xca,0xc7,0xe4,0xe9,0xfe,0xf3,0xb8,0xb5,0xa2,0xaf,0x8c,0x81,0x96,0x9b},
                                    {0xbb,0xb6,0xa1,0xac,0x8f,0x82,0x95,0x98,0xd3,0xde,0xc9,0xc4,0xe7,0xea,0xfd,0xf0},
                                    {0x6b,0x66,0x71,0x7c,0x5f,0x52,0x45,0x48,0x03,0x0e,0x19,0x14,0x37,0x3a,0x2d,0x20},
                                    {0x6d,0x60,0x77,0x7a,0x59,0x54,0x43,0x4e,0x05,0x08,0x1f,0x12,0x31,0x3c,0x2b,0x26},
                                    {0xbd,0xb0,0xa7,0xaa,0x89,0x84,0x93,0x9e,0xd5,0xd8,0xcf,0xc2,0xe1,0xec,0xfb,0xf6},
                                    {0xd6,0xdb,0xcc,0xc1,0xe2,0xef,0xf8,0xf5,0xbe,0xb3,0xa4,0xa9,0x8a,0x87,0x90,0x9d},
                                    {0x06,0x0b,0x1c,0x11,0x32,0x3f,0x28,0x25,0x6e,0x63,0x74,0x79,0x5a,0x57,0x40,0x4d},
                                    {0xda,0xd7,0xc0,0xcd,0xee,0xe3,0xf4,0xf9,0xb2,0xbf,0xa8,0xa5,0x86,0x8b,0x9c,0x91},
                                    {0x0a,0x07,0x10,0x1d,0x3e,0x33,0x24,0x29,0x62,0x6f,0x78,0x75,0x56,0x5b,0x4c,0x41},
                                    {0x61,0x6c,0x7b,0x76,0x55,0x58,0x4f,0x42,0x09,0x04,0x13,0x1e,0x3d,0x30,0x27,0x2a},
                                    {0xb1,0xbc,0xab,0xa6,0x85,0x88,0x9f,0x92,0xd9,0xd4,0xc3,0xce,0xed,0xe0,0xf7,0xfa},
                                    {0xb7,0xba,0xad,0xa0,0x83,0x8e,0x99,0x94,0xdf,0xd2,0xc5,0xc8,0xeb,0xe6,0xf1,0xfc},
                                    {0x67,0x6a,0x7d,0x70,0x53,0x5e,0x49,0x44,0x0f,0x02,0x15,0x18,0x3b,0x36,0x21,0x2c},
                                    {0x0c,0x01,0x16,0x1b,0x38,0x35,0x22,0x2f,0x64,0x69,0x7e,0x73,0x50,0x5d,0x4a,0x47},
                                    {0xdc,0xd1,0xc6,0xcb,0xe8,0xe5,0xf2,0xff,0xb4,0xb9,0xae,0xa3,0x80,0x8d,0x9a,0x97}   };

    public static int[][] mul_14 = {  {0x00,0x0e,0x1c,0x12,0x38,0x36,0x24,0x2a,0x70,0x7e,0x6c,0x62,0x48,0x46,0x54,0x5a},
                                    {0xe0,0xee,0xfc,0xf2,0xd8,0xd6,0xc4,0xca,0x90,0x9e,0x8c,0x82,0xa8,0xa6,0xb4,0xba},
                                    {0xdb,0xd5,0xc7,0xc9,0xe3,0xed,0xff,0xf1,0xab,0xa5,0xb7,0xb9,0x93,0x9d,0x8f,0x81},
                                    {0x3b,0x35,0x27,0x29,0x03,0x0d,0x1f,0x11,0x4b,0x45,0x57,0x59,0x73,0x7d,0x6f,0x61},
                                    {0xad,0xa3,0xb1,0xbf,0x95,0x9b,0x89,0x87,0xdd,0xd3,0xc1,0xcf,0xe5,0xeb,0xf9,0xf7},
                                    {0x4d,0x43,0x51,0x5f,0x75,0x7b,0x69,0x67,0x3d,0x33,0x21,0x2f,0x05,0x0b,0x19,0x17},
                                    {0x76,0x78,0x6a,0x64,0x4e,0x40,0x52,0x5c,0x06,0x08,0x1a,0x14,0x3e,0x30,0x22,0x2c},
                                    {0x96,0x98,0x8a,0x84,0xae,0xa0,0xb2,0xbc,0xe6,0xe8,0xfa,0xf4,0xde,0xd0,0xc2,0xcc},
                                    {0x41,0x4f,0x5d,0x53,0x79,0x77,0x65,0x6b,0x31,0x3f,0x2d,0x23,0x09,0x07,0x15,0x1b},
                                    {0xa1,0xaf,0xbd,0xb3,0x99,0x97,0x85,0x8b,0xd1,0xdf,0xcd,0xc3,0xe9,0xe7,0xf5,0xfb},
                                    {0x9a,0x94,0x86,0x88,0xa2,0xac,0xbe,0xb0,0xea,0xe4,0xf6,0xf8,0xd2,0xdc,0xce,0xc0},
                                    {0x7a,0x74,0x66,0x68,0x42,0x4c,0x5e,0x50,0x0a,0x04,0x16,0x18,0x32,0x3c,0x2e,0x20},
                                    {0xec,0xe2,0xf0,0xfe,0xd4,0xda,0xc8,0xc6,0x9c,0x92,0x80,0x8e,0xa4,0xaa,0xb8,0xb6},
                                    {0x0c,0x02,0x10,0x1e,0x34,0x3a,0x28,0x26,0x7c,0x72,0x60,0x6e,0x44,0x4a,0x58,0x56},
                                    {0x37,0x39,0x2b,0x25,0x0f,0x01,0x13,0x1d,0x47,0x49,0x5b,0x55,0x7f,0x71,0x63,0x6d},
                                    {0xd7,0xd9,0xcb,0xc5,0xef,0xe1,0xf3,0xfd,0xa7,0xa9,0xbb,0xb5,0x9f,0x91,0x83,0x8d}};
    
    // simple left rotate over an array
	private int[] leftrotate(int[] arr, int times)
    {
        assert(arr.length == 4);
        if (times % 4 == 0) {
            return arr;
        }
        while (times > 0) {
            int temp = arr[0];
            for (int i = 0; i < arr.length - 1; i++) {
                arr[i] = arr[i + 1];
            }
            arr[arr.length - 1] = temp;
            --times;
        }
        return arr;
    }
	
    // simple right rotate
	private int[] rightrotate(int[] arr, int times) {
        if (arr.length == 0 || arr.length == 1 || times % 4 == 0) {
            return arr;
        }
        while (times > 0) {
            int temp = arr[arr.length - 1];
            for (int i = arr.length - 1; i > 0; i--) {
                arr[i] = arr[i - 1];
            }
            arr[0] = temp;
            --times;
        }
        return arr;
    }
	
    // function for column mix step
	public void mixColumns(int[][] state, boolean encrypt) 
    {
		int [][] tarr = new int [4][4];
		for(int i = 0; i < 4; i++)
        {
            System.arraycopy(state[i], 0, tarr[i], 0, 4);
        }
        int mcsum;
        int x, y;
        
        for (int i = 0; i < 4; i++) {
            for (int j = 0; j < 4; j++) {
                mcsum = 0;
                if(encrypt){
                    for (int k = 0; k < 4; k++) {
                        x = galois[i][k];
                        y = tarr[k][j];
                        mcsum ^= encMixedColumns(x, y);
                    }
                }else{
                    for (int k = 0; k < 4; k++) {
                        x = invgalois[i][k];
                        y = tarr[k][j];
                        mcsum ^= decMixedColumns(x, y);
                    }
                }
                state[i][j] = mcsum;
            }
        }
    }
    
	// helper function for mix column function on encrypt
    private int encMixedColumns(int x, int y) 
    {
        if (x == 1) {
            return y;
        } else if (x == 2) {
            return mul_2[y / 16][y % 16];
        } else if (x == 3) {
            return mul_3[y / 16][y % 16];
        }
        return 0;
    }
    
	// helper function for mix column function on decrypt
    private int decMixedColumns(int x, int y) 
    {
        if (x == 9) {
            return mul_9[y / 16][y % 16];
        } else if (x == 11) {
            return mul_11[y / 16][y % 16];
        } else if (x == 13) {
            return mul_13[y / 16][y % 16];
        } else if (x == 14) {
            return mul_14[y / 16][y % 16];
        }
        return 0;
    }
	
    // xor 2 4x4 matrices
    public void addRoundKey(int[][] bytematrix, int[][] keymatrix)
    {
        for (int i = 0; i < bytematrix.length; i++) {
            for (int j = 0; j < bytematrix[0].length; j++) {
                bytematrix[j][i] ^= keymatrix[j][i];
            }
        }
    }
    
    // create a round key matrix using 32 hexadecimal characters of key string
    public int[][] keySchedule(String key)
    {
        // key size in binary, key is 32 hex-characters -> binkeysize is 128-bit
        int binkeysize = key.length() * 4;
        
        // number of blocks in round key matrix, 128 -> 11*16 blocks, 192 -> 13*16 blocks, 256 -> 15*16 blocks
        int block_size = binkeysize*3/2 - 16;
        
        // number of columns in round key matrix, (128 -> 11*4), (192 -> 13*4), (256 -> 15*4)
        int colsize = block_size / 4;
        
        
        // round key matrix, 4x44, 4x52, 4x60
        int[][] keyMatrix = new int[4][colsize]; 
        
        // pointer that points to the specific place on rcon matrix, changes in the schedule_core func
        int rconpointer = 1;
        
        // t is a column of round key matrix
        int[] t = new int[4];
        
        // keycounter is 4, at each round 4 columns are processed for 128 bit
        final int keycounter = binkeysize / 32;
        
        // k is the row index
        int k;
        
        // initial step, define the first 4*4 (for 128 bit) matrix
        for (int i = 0; i < keycounter; i++) //the first 1 (128-bit key) or 2 (256-bit key) set(s) of 4x4 matrices are filled with the key.
        {
            for (int j = 0; j < 4; j++) {
                keyMatrix[j][i] = Integer.parseInt(key.substring((8 * i) + (2 * j), (8 * i) + (2 * j + 2)), 16);
            }
        }
        
        // keypoint is the column index
        int keypoint = keycounter;
        
        // create each column 
        while (keypoint < colsize) {
            int temp = keypoint % keycounter;
            if (temp == 0) {
                for (k = 0; k < 4; k++) {
                    t[k] = keyMatrix[k][keypoint - 1];
                }
                t = schedule_core(t, rconpointer++);
                for (k = 0; k < 4; k++) {
                    keyMatrix[k][keypoint] = t[k] ^ keyMatrix[k][keypoint - keycounter];
                }
                keypoint++;
            } else if (temp == 4) {
                for (k = 0; k < 4; k++) {
                    int hex = keyMatrix[k][keypoint - 1];
                    keyMatrix[k][keypoint] = subTable[hex / 16][hex % 16] ^ keyMatrix[k][keypoint - keycounter];
                }
                keypoint++;
            } else {
                int ktemp = keypoint + 3;
                while (keypoint < ktemp) {
                    for (k = 0; k < 4; k++) {
                        keyMatrix[k][keypoint] = keyMatrix[k][keypoint - 1] ^ keyMatrix[k][keypoint - keycounter];
                    }
                    keypoint++;
                }
            }
        }
        return keyMatrix;
    }
    
    // using rcon matrix, round key matrix is generated (xor step)
    public int[] schedule_core(int[] in, int rconpointer) {
        in = leftrotate(in, 1);
        int hex;
        for (int i = 0; i < in.length; i++) {
            hex = in[i];
            in[i] = subTable[hex / 16][hex % 16];
        }
        in[0] ^= rcon[rconpointer];
        return in;
    }
}