DES加密算法源码（java版）

原文：http://blog.youkuaiyun.com/zyg158/article/details/1667535

public class DES {
    // 声明常量字节数组
    private 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
        }; // 64
    private static final int[] IP_1 = {
            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
        }; // 64
    private static final int[] PC_1 = {
            57, 49, 41, 33, 25, 17, 9, 1, 58, 50, 42, 34, 26, 18, 10, 2, 59, 51,
            43, 35, 27, 19, 11, 3, 60, 52, 44, 36, 63, 55, 47, 39, 31, 23, 15, 7,
            62, 54, 46, 38, 30, 22, 14, 6, 61, 53, 45, 37, 29, 21, 13, 5, 28, 20,
            12, 4
        }; // 56
    private static final int[] PC_2 = {
            14, 17, 11, 24, 1, 5, 3, 28, 15, 6, 21, 10, 23, 19, 12, 4, 26, 8, 16,
            7, 27, 20, 13, 2, 41, 52, 31, 37, 47, 55, 30, 40, 51, 45, 33, 48, 44,
            49, 39, 56, 34, 53, 46, 42, 50, 36, 29, 32
        }; // 48
    private 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
        }; // 48
    private 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
        }; // 32
    private static final int[][][] S_Box = {
            {
                { 14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7 },
                { 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 }
            },
            { // S_Box[1]
                { 15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10 },
                { 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 }
            },
            { // S_Box[2]
                { 10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8 },
                { 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 }
            },
            { // S_Box[3]
                { 7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15 },
                { 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 }
            },
            { // S_Box[4]
                { 2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9 },
                { 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 }
            },
            { // S_Box[5]
                { 12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11 },
                { 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 }
            },
            { // S_Box[6]
                { 4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1 },
                { 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 }
            },
            { // S_Box[7]
                { 13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7 },
                { 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 }
            } // S_Box[8]
        };
    private static final int[] LeftMove = {
            1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1
        }; // 左移位置列表

    private byte[] UnitDes(byte[] des_key, byte[] des_data, int flag) {
        // 检测输入参数格式是否正确，错误直接返回空值（null）
        if ((des_key.length != 8) || (des_data.length != 8) ||
                ((flag != 1) && (flag != 0))) {
            throw new RuntimeException("Data Format Error !");
        }

        int flags = flag;

        // 二进制加密密钥
        int[] keydata = new int[64];

        // 二进制加密数据
        int[] encryptdata = new int[64];

        // 加密操作完成后的字节数组
        byte[] EncryptCode = new byte[8];

        // 密钥初试化成二维数组
        int[][] KeyArray = new int[16][48];
        // 将密钥字节数组转换成二进制字节数组
        keydata = ReadDataToBirnaryIntArray(des_key);
        // 将加密数据字节数组转换成二进制字节数组
        encryptdata = ReadDataToBirnaryIntArray(des_data);
        // 初试化密钥为二维密钥数组
        KeyInitialize(keydata, KeyArray);
        // 执行加密解密操作
        EncryptCode = Encrypt(encryptdata, flags, KeyArray);

        return EncryptCode;
    }

    // 初试化密钥数组
    private void KeyInitialize(int[] key, int[][] keyarray) {
        int i;
        int j;
        int[] K0 = new int[56];

        // 特别注意：xxx[IP[i]-1]等类似变换
        for (i = 0; i < 56; i++) {
            K0[i] = key[PC_1[i] - 1]; // 密钥进行PC-1变换
        }

        for (i = 0; i < 16; i++) {
            LeftBitMove(K0, LeftMove[i]);

            // 特别注意：xxx[IP[i]-1]等类似变换
            for (j = 0; j < 48; j++) {
                keyarray[i][j] = K0[PC_2[j] - 1]; // 生成子密钥keyarray[i][j]
            }
        }
    }

    // 执行加密解密操作
    private byte[] Encrypt(int[] timeData, int flag, int[][] keyarray) {
        int i;
        byte[] encrypt = new byte[8];
        int flags = flag;
        int[] M = new int[64];
        int[] MIP_1 = new int[64];

        // 特别注意：xxx[IP[i]-1]等类似变换
        for (i = 0; i < 64; i++) {
            M[i] = timeData[IP[i] - 1]; // 明文IP变换
        }

        if (flags == 1) { // 加密

            for (i = 0; i < 16; i++) {
                LoopF(M, i, flags, keyarray);
            }
        } else if (flags == 0) { // 解密

            for (i = 15; i > -1; i--) {
                LoopF(M, i, flags, keyarray);
            }
        }

        for (i = 0; i < 64; i++) {
            MIP_1[i] = M[IP_1[i] - 1]; // 进行IP-1运算
        }

        GetEncryptResultOfByteArray(MIP_1, encrypt);

        // 返回加密数据
        return encrypt;
    }

    private int[] ReadDataToBirnaryIntArray(byte[] intdata) {
        int i;
        int j;

        // 将数据转换为二进制数，存储到数组
        int[] IntDa = new int[8];

        for (i = 0; i < 8; i++) {
            IntDa[i] = intdata[i];

            if (IntDa[i] < 0) {
                IntDa[i] += 256;
                IntDa[i] %= 256;
            }
        }

        int[] IntVa = new int[64];

        for (i = 0; i < 8; i++) {
            for (j = 0; j < 8; j++) {
                IntVa[((i * 8) + 7) - j] = IntDa[i] % 2;
                IntDa[i] = IntDa[i] / 2;
            }
        }

        return IntVa;
    }

    private void LeftBitMove(int[] k, int offset) {
        int i;

        // 循环移位操作函数
        int[] c0 = new int[28];
        int[] d0 = new int[28];
        int[] c1 = new int[28];
        int[] d1 = new int[28];

        for (i = 0; i < 28; i++) {
            c0[i] = k[i];
            d0[i] = k[i + 28];
        }

        if (offset == 1) {
            for (i = 0; i < 27; i++) { // 循环左移一位
                c1[i] = c0[i + 1];
                d1[i] = d0[i + 1];
            }

            c1[27] = c0[0];
            d1[27] = d0[0];
        } else if (offset == 2) {
            for (i = 0; i < 26; i++) { // 循环左移两位
                c1[i] = c0[i + 2];
                d1[i] = d0[i + 2];
            }

            c1[26] = c0[0];
            d1[26] = d0[0];
            c1[27] = c0[1];
            d1[27] = d0[1];
        }

        for (i = 0; i < 28; i++) {
            k[i] = c1[i];
            k[i + 28] = d1[i];
        }
    }

    private void LoopF(int[] M, int times, int flag, int[][] keyarray) {
        int i;
        int j;
        int[] L0 = new int[32];
        int[] R0 = new int[32];
        int[] L1 = new int[32];
        int[] R1 = new int[32];
        int[] RE = new int[48];
        int[][] S = new int[8][6];
        int[] sBoxData = new int[8];
        int[] sValue = new int[32];
        int[] RP = new int[32];

        for (i = 0; i < 32; i++) {
            L0[i] = M[i]; // 明文左侧的初始化
            R0[i] = M[i + 32]; // 明文右侧的初始化
        }

        for (i = 0; i < 48; i++) {
            RE[i] = R0[E[i] - 1]; // 经过E变换扩充，由32位变为48位
            RE[i] = RE[i] + keyarray[times][i]; // 与KeyArray[times][i]按位作不进位加法运算

            if (RE[i] == 2) {
                RE[i] = 0;
            }
        }

        for (i = 0; i < 8; i++) { // 48位分成8组

            for (j = 0; j < 6; j++) {
                S[i][j] = RE[(i * 6) + j];
            }

            // 下面经过S盒，得到8个数
            sBoxData[i] = S_Box[i][(S[i][0] << 1) + S[i][5]][(S[i][1] << 3) +
                (S[i][2] << 2) + (S[i][3] << 1) + S[i][4]];

            // 8个数变换输出二进制
            for (j = 0; j < 4; j++) {
                sValue[((i * 4) + 3) - j] = sBoxData[i] % 2;
                sBoxData[i] = sBoxData[i] / 2;
            }
        }

        for (i = 0; i < 32; i++) {
            RP[i] = sValue[P[i] - 1]; // 经过P变换
            L1[i] = R0[i]; // 右边移到左边
            R1[i] = L0[i] + RP[i];

            if (R1[i] == 2) {
                R1[i] = 0;
            }

            // 重新合成M，返回数组M
            // 最后一次变换时，左右不进行互换。此处采用两次变换实现不变
            if (((flag == 0) && (times == 0)) ||
                    ((flag == 1) && (times == 15))) {
                M[i] = R1[i];
                M[i + 32] = L1[i];
            } else {
                M[i] = L1[i];
                M[i + 32] = R1[i];
            }
        }
    }

    private void GetEncryptResultOfByteArray(int[] data, byte[] value) {
        int i;
        int j;

        // 将存储64位二进制数据的数组中的数据转换为八个整数（byte）
        for (i = 0; i < 8; i++) {
            for (j = 0; j < 8; j++) {
                value[i] += (data[(i << 3) + j] << (7 - j));
            }
        }

        for (i = 0; i < 8; i++) {
            value[i] %= 256;

            if (value[i] > 128) {
                value[i] -= 255;
            }
        }
    }

    private byte[] ByteDataFormat(byte[] data, int flag) {
        int len = data.length;
        int padlen = 8 - (len % 8);
        int newlen = len + padlen;
        byte[] newdata = new byte[newlen];
        System.arraycopy(data, 0, newdata, 0, len);

        for (int i = len; i < newlen; i++)
            newdata[i] = (byte) padlen;

        return newdata;
    }

    public byte[] DesEncrypt(byte[] des_key, byte[] des_data, int flag) {
        byte[] format_key = ByteDataFormat(des_key, flag);
        byte[] format_data = ByteDataFormat(des_data, flag);
        int datalen = format_data.length;
        int unitcount = datalen / 8;
        byte[] result_data = new byte[datalen];

        for (int i = 0; i < unitcount; i++) {
            byte[] tmpkey = new byte[8];
            byte[] tmpdata = new byte[8];
            System.arraycopy(format_key, 0, tmpkey, 0, 8);
            System.arraycopy(format_data, i * 8, tmpdata, 0, 8);

            byte[] tmpresult = UnitDes(tmpkey, tmpdata, flag);
            System.arraycopy(tmpresult, 0, result_data, i * 8, 8);
        }

        // 当前为解密过程，去掉加密时产生的填充位
        byte[] decryptbytearray = null;

        if (flag == 0) {
            int total_len = datalen;
            int delete_len = result_data[total_len - 8 - 1];
            delete_len = ((delete_len >= 1) && (delete_len <= 8)) ? delete_len : 0;
            decryptbytearray = new byte[total_len - delete_len - 8];

            boolean del_flag = true;

            for (int k = 0; k < delete_len; k++) {
                if (delete_len != result_data[total_len - 8 - (k + 1)])
                    del_flag = false;
            }

            if (del_flag == true) {
                System.arraycopy(result_data, 0, decryptbytearray, 0,
                    total_len - delete_len - 8);
            }
        }

        return (flag == 1) ? result_data : decryptbytearray;
    }

    public static void main(String[] args) {
        String key = "00000000";
        String data = "11111111";
        int bytelen = data.getBytes().length;
        byte[] result = new byte[(bytelen + 8) - (bytelen % 8)];
        byte[] bytekey = key.getBytes();
        byte[] bytedata = data.getBytes();

        for (int i = 0; i < bytedata.length; i++) {
            System.out.print(" " + bytedata[i] + " ");
        }

        System.out.println();

        DES des = new DES();
        result = des.DesEncrypt(bytekey, bytedata, 1);

        for (int i = 0; i < result.length; i++) {
            System.out.print(" " + result[i] + " ");
        }

        System.out.println();
        result = des.DesEncrypt(bytekey, result, 0);

        for (int i = 0; i < result.length; i++) {
            System.out.print(" " + result[i] + " ");
        }

        System.out.println();
    }
}