desciphertest.java

DES RSA 加密解密算法类

package des;

/**
 * DESCipherTest.java
 */
public class DESCipherTest {
    
    public static void main(String[] a) {
        try {
            byte[][] subKeys = getTestSubkeys();
            byte[] theMsg = getTestMsg();
            byte[] theCph = cipherBlock(theMsg, subKeys);
            boolean ok = validateCipher(theCph);
            System.out.println("DES cipher test result: " + ok);
        } catch (Exception e) {
            e.printStackTrace();
            return;
        }
    }

    static final int[] IP = { 58, 50, 42, 34, 26, 18, 10, 2, 60, 52, 44, 36,
            28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48, 40, 32,
            24, 16, 8, 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35, 27, 19,
            11, 3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31, 23, 15, 7 };

    static final int[] E = { 32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9, 10, 11,
            12, 13, 12, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20, 21, 22,
            23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1 };

    static final int[] P = { 16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5,
            18, 31, 10, 2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4,
            25 };

    static final int[] FP = { 40, 8, 48, 16, 56, 24, 64, 32, 39, 7, 47, 15, 55,
            23, 63, 31, 38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45, 13, 53, 21,
            61, 29, 36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11, 51, 19, 59,
            27, 34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49, 17, 57, 25 };

    private static byte[] cipherBlock(byte[] theMsg, byte[][] subKeys)
            throws Exception {
        if (theMsg.length < 8)
            throw new Exception("Message is less than 64 bits.");
        printBytes(theMsg, "Input message");
        theMsg = selectBits(theMsg, IP); // Initial Permutation
        printBytes(theMsg, "After initial permutation");
        int blockSize = IP.length;
        byte[] l = selectBits(theMsg, 0, blockSize / 2);
        byte[] r = selectBits(theMsg, blockSize / 2, blockSize / 2);
        int numOfSubKeys = subKeys.length;
        for (int k = 0; k < numOfSubKeys; k++) {
            byte[] rBackup = r;
            r = selectBits(r, E); // Expansion
            printBytes(r, "R: After E expansion");
            r = doXORBytes(r, subKeys[k]); // XOR with the sub key
            printBytes(r, "R: After XOR with the subkey");
            r = substitution6x4(r); // Substitution
            printBytes(r, "R: After S boxes");
            r = selectBits(r, P); // Permutation
            printBytes(r, "R: After P permutation");
            r = doXORBytes(l, r); // XOR with the previous left half
            printBytes(r, "Right half at round #" + (k + 1));
            l = rBackup; // Taking the previous right half
        }
        byte[] lr = concatenateBits(r, blockSize / 2, l, blockSize / 2);
        printBytes(lr, "After 16 rounds");
        lr = selectBits(lr, FP); // Inverse Permutation
        printBytes(lr, "After final permutation");
        return lr;
    }

    private static byte[] doXORBytes(byte[] a, byte[] b) {
        byte[] out = new byte[a.length];
        for (int i = 0; i < a.length; i++) {
            out[i] = (byte) (a[i] ^ b[i]);
        }
        return out;
    }

    static final int[] S = { 14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0,
            7, // S1
            0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8, 4, 1, 14, 8,
            13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0, 15, 12, 8, 2, 4, 9, 1, 7,
            5, 11, 3, 14, 10, 0, 6, 13, 15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13,
            12, 0, 5, 10, // S2
            3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5, 0, 14, 7, 11,
            10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15, 13, 8, 10, 1, 3, 15, 4, 2,
            11, 6, 7, 12, 0, 5, 14, 9, 10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7,
            11, 4, 2, 8, // S3
            13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1, 13, 6, 4, 9,
            8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7, 1, 10, 13, 0, 6, 9, 8, 7,
            4, 15, 14, 3, 11, 5, 2, 12, 7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5,
            11, 12, 4, 15, // S4
            13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9, 10, 6, 9, 0,
            12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4, 3, 15, 0, 6, 10, 1, 13, 8,
            9, 4, 5, 11, 12, 7, 2, 14, 2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15,
            13, 0, 14, 9, // S5
            14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6, 4, 2, 1, 11,
            10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14, 11, 8, 12, 7, 1, 14, 2,
            13, 6, 15, 0, 9, 10, 4, 5, 3, 12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3,
            4, 14, 7, 5, 11, // S6
            10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8, 9, 14, 15, 5,
            2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6, 4, 3, 2, 12, 9, 5, 15, 10,
            11, 14, 1, 7, 6, 0, 8, 13, 4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7,
            5, 10, 6, 1, // S7
            13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6, 1, 4, 11, 13,
            12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2, 6, 11, 13, 8, 1, 4, 10, 7,
            9, 5, 0, 15, 14, 2, 3, 12, 13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14,
            5, 0, 12, 7, // S8
            1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2, 7, 11, 4, 1,
            9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8, 2, 1, 14, 7, 4, 10, 8, 13,
            15, 12, 9, 0, 3, 5, 6, 11 };

    private static byte[] substitution6x4(byte[] in) {
        in = splitBytes(in, 6); // Splitting byte[] into 6-bit blocks
        // printBytes(in,"R: After splitting");
        byte[] out = new byte[in.length / 2];
        int lhByte = 0;
        for (int b = 0; b < in.length; b++) { // Should be sub-blocks
            byte valByte = in[b];
            int r = 2 * (valByte >> 7 & 0x0001) + (valByte >> 2 & 0x0001); // 1
                                                                            // and
                                                                            // 6
            int c = valByte >> 3 & 0x000F; // Middle 4 bits
            int hByte = S[64 * b + 16 * r + c]; // 4 bits (half byte) output
            if (b % 2 == 0)
                lhByte = hByte; // Left half byte
            else
                out[b / 2] = (byte) (16 * lhByte + hByte);
        }
        return out;
    }

    private static byte[] splitBytes(byte[] in, int len) {
        int numOfBytes = (8 * in.length - 1) / len + 1;
        byte[] out = new byte[numOfBytes];
        for (int i = 0; i < numOfBytes; i++) {
            for (int j = 0; j < len; j++) {
                int val = getBit(in, len * i + j);
                setBit(out, 8 * i + j, val);
            }
        }
        return out;
    }

    private static byte[] concatenateBits(byte[] a, int aLen, byte[] b, int bLen) {
        int numOfBytes = (aLen + bLen - 1) / 8 + 1;
        byte[] out = new byte[numOfBytes];
        int j = 0;
        for (int i = 0; i < aLen; i++) {
            int val = getBit(a, i);
            setBit(out, j, val);
            j++;
        }
        for (int i = 0; i < bLen; i++) {
            int val = getBit(b, i);
            setBit(out, j, val);
            j++;
        }
        return out;
    }

    private static byte[] selectBits(byte[] in, int pos, int len) {
        int numOfBytes = (len - 1) / 8 + 1;
        byte[] out = new byte[numOfBytes];
        for (int i = 0; i < len; i++) {
            int val = getBit(in, pos + i);
            setBit(out, i, val);
        }
        return out;
    }

    private static byte[] selectBits(byte[] in, int[] map) {
        int numOfBytes = (map.length - 1) / 8 + 1;
        byte[] out = new byte[numOfBytes];
        for (int i = 0; i < map.length; i++) {
            int val = getBit(in, map[i] - 1);
            setBit(out, i, val);
            // System.out.println("i="+i+", pos="+(map[i]-1)+", val="+val);
        }
        return out;
    }

    private static int getBit(byte[] data, int pos) {
        int posByte = pos / 8;
        int posBit = pos % 8;
        byte valByte = data[posByte];
        int valInt = valByte >> (8 - (posBit + 1)) & 0x0001;
        return valInt;
    }

    private static void setBit(byte[] data, int pos, int val) {
        int posByte = pos / 8;
        int posBit = pos % 8;
        byte oldByte = data[posByte];
        oldByte = (byte) (((0xFF7F >> posBit) & oldByte) & 0x00FF);
        byte newByte = (byte) ((val << (8 - (posBit + 1))) | oldByte);
        data[posByte] = newByte;
    }

    private static void printBytes(byte[] data, String name) {
        System.out.println("");
        System.out.println(name + ":");
        for (int i = 0; i < data.length; i++) {
            System.out.print(byteToBits(data[i]) + " ");
        }
        System.out.println();
    }

    private static String byteToBits(byte b) {
        StringBuffer buf = new StringBuffer();
        for (int i = 0; i < 8; i++)
            buf.append((int) (b >> (8 - (i + 1)) & 0x0001));
        return buf.toString();
    }

    private static byte[][] getTestSubkeys() {
        String[] strKeys = {
                " 00011011 00000010 11101111 11111100 01110000 01110010",// 1
                " 01111001 10101110 11011001 11011011 11001001 11100101",// 2
                " 01010101 11111100 10001010 01000010 11001111 10011001",// 3
                " 01110010 10101101 11010110 11011011 00110101 00011101",// 4
                " 01111100 11101100 00000111 11101011 01010011 10101000",// 5
                " 01100011 10100101 00111110 01010000 01111011 00101111",// 6
                " 11101100 10000100 10110111 11110110 00011000 10111100",// 7
                " 11110111 10001010 00111010 11000001 00111011 11111011",// 8
                " 11100000 11011011 11101011 11101101 11100111 10000001",// 9
                " 10110001 11110011 01000111 10111010 01000110 01001111",// 0
                " 00100001 01011111 11010011 11011110 11010011 10000110",// 1
                " 01110101 01110001 11110101 10010100 01100111 11101001",// 2
                " 10010111 11000101 11010001 11111010 10111010 01000001",// 3
                " 01011111 01000011 10110111 11110010 11100111 00111010",// 4
                " 10111111 10010001 10001101 00111101 00111111 00001010",// 5
                " 11001011 00111101 10001011 00001110 00010111 11110101" };
        byte[][] subKeys = new byte[16][];
        for (int k = 0; k < 16; k++) {
            byte[] theKey = new byte[6];
            for (int i = 0; i < 6; i++) {
                String strByte = strKeys[k].substring(9 * i + 1, 9 * i + 1 + 8);
                theKey[i] = (byte) Integer.parseInt(strByte, 2);
            }
            subKeys[k] = theKey;
        }
        return subKeys;
    }

    private static byte[] getTestMsg() {
        String strMsg = " 00000001 00100011 01000101 01100111"
                + " 10001001 10101011 11001101 11101111";
        byte[] theMsg = new byte[8];
        for (int i = 0; i < 8; i++) {
            String strByte = strMsg.substring(9 * i + 1, 9 * i + 1 + 8);
            theMsg[i] = (byte) Integer.parseInt(strByte, 2);
        }
        return theMsg;
    }

    private static boolean validateCipher(byte[] cipher) {
        String strCipher = " 10000101 11101000 00010011 01010100"
                + " 00001111 00001010 10110100 00000101";
        boolean ok = true;
        for (int i = 0; i < 8; i++) {
            String strByte = strCipher.substring(9 * i + 1, 9 * i + 1 + 8);
            byte cipherByte = (byte) Integer.parseInt(strByte, 2);
            if (cipherByte != cipher[i])
                ok = false;
        }
        return ok;
    }
}