欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页

DES通用加密解密类

程序员文章站 2022-03-12 19:01:20
...
  1. DES加密介绍
    DES是一种对称加密算法,所谓对称加密算法即:加密和解密使用相同**的算法。DES加密算法出自IBM的研究,后来被美国*正式采用,之后开始广泛流传,但是近些年使用越来越少,因为DES使用56位**,以现代计算能力,24小时内即可被**。虽然如此,在某些简单应用中,我们还是可以使用DES加密算法,本文简单讲解DES的JAVA实现.
public class DES {

    private final static String strDefaultKey = "password";

    /**
     * **为8位,不能多不能少,指定key,则key+DefaultKey后截前8位
     */
    private String strKey = strDefaultKey;

    public String digestHexStr;
    // 28
    static final int pc_1_cp[] = { 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 };
    // 28
    static final int pc_1_dp[] = { 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 };
    // 48
    static final int pc_2p[] = { 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 };
    // 16
    static final int ls_countp[] = { 1, 1, 2, 2, 2, 2, 2, 2, 1, 2, 2, 2, 2, 2, 2, 1 };
    // 64
    static final int iip_tab_p[] = { 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
    static final int _iip_tab_p[] = { 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 };
    // 48
    static final int e_r_p[] = { 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 };
    // 32
    static final int local_PP[] = { 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 };
    // [8][4][16]
    static final int ccom_SSS_p[][][] = {
            { { 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 } },

            { { 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 } },

            { { 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 } },

            { { 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 } }, /*
                                                                                 * err
                                                                                 * on
                                                                                 */

            { { 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 }, /*
                                                                             * err
                                                                             * on
                                                                             */
                    { 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 },
                    { 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 },
                    { 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 },
                    { 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 } } };

    byte[][] C = new byte[17][28];
    byte[][] D = new byte[17][28];
    byte[][] K = new byte[17][48];

    public DES() {
        return;
    }

    /**
     * **小于8位,补足8位,超过8位,截取前8位 总之**为8位字符
     * 
     * @param key
     */
    public DES(String key) {
        this.strKey = String.valueOf(key + strDefaultKey).substring(0, 8);
        return;
    }

    /*
     * iu2b把int转换成byte
     */
    private static byte iu2b(int input) {
        byte output1;
        output1 = (byte) (input & 0xff);
        return output1;
    }

    /*
     * b2iu把byte按照不考虑正负号的原则的"升位"成int程序, 因为java没有unsigned运算
     */
    private static int b2iu(byte b) {
        return b < 0 ? b & 0x7F + 128 : b;
    }

    /*
     * byteHEX(),用来把一个byte类型的数转换成十六进制的ASCII表示,
     * 因为java中的byte的toString无法实现这一点,我们又没有C语言中的 sprintf(outbuf,"%02X",ib)
     */
    public static String byteHEX(byte ib) {
        char[] Digit = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E',
                'F' };
        char[] ob = new char[2];
        ob[0] = Digit[(ib >>> 4) & 0X0F];
        ob[1] = Digit[ib & 0X0F];
        String s = new String(ob);
        return s;
    }

    /*
     * desMemcpy是一个内部使用的byte数组的块拷贝函数, 从input的inpos开始把len长度的
     * 字节拷贝到output的outpos位置开始
     */
    private void desMemcpy(byte[] output, byte[] input, int outpos, int inpos, int len) {
        int i;
        for (i = 0; i < len; i++)
            output[outpos + i] = input[inpos + i];
    }

    private void Fexpand0(byte[] in, byte[] out) {
        int divide;
        int i, j;
        byte temp1;

        for (i = 0; i < 8; i++) {
            divide = 7;
            for (j = 0; j < 8; j++) {
                temp1 = in[i];
                out[8 * i + j] = iu2b((b2iu(temp1) >>> divide) & 1);
                divide--;
            }
        }
    }

    private void FLS(byte[] bits, byte[] buffer, int count) {
        int i;
        for (i = 0; i < 28; i++) {
            buffer[i] = bits[(i + count) % 28];
        }
    }

    private void Fson(byte[] cc, byte[] dd, byte[] kk) {
        int i;
        byte[] buffer = new byte[56];
        for (i = 0; i < 28; i++)
            buffer[i] = cc[i];

        for (i = 28; i < 56; i++)
            buffer[i] = dd[i - 28];

        for (i = 0; i < 48; i++)
            kk[i] = buffer[pc_2p[i] - 1];
    }

    private void Fsetkeystar(byte[] bits) {
        int i, j;

        for (i = 0; i < 28; i++)
            C[0][i] = bits[pc_1_cp[i] - 1];
        for (i = 0; i < 28; i++)
            D[0][i] = bits[pc_1_dp[i] - 1];
        for (j = 0; j < 16; j++) {
            FLS(C[j], C[j + 1], ls_countp[j]);
            FLS(D[j], D[j + 1], ls_countp[j]);
            Fson(C[j + 1], D[j + 1], K[j + 1]);
        }
    }

    private void Fiip(byte[] text, byte[] ll, byte[] rr) {
        int i;
        byte[] buffer = new byte[64];
        //byte[] tmp = new byte[64];
        Fexpand0(text, buffer);

        for (i = 0; i < 32; i++)
            ll[i] = buffer[iip_tab_p[i] - 1];

        for (i = 0; i < 32; i++)
            rr[i] = buffer[iip_tab_p[i + 32] - 1];
    }

    private void Fs_box(byte[] aa, byte[] bb) {
        int i, j, k, m;
        int y, z;
        byte[] ss = new byte[8];
        m = 0;
        for (i = 0; i < 8; i++) {
            j = 6 * i;
            y = b2iu(aa[j]) * 2 + b2iu(aa[j + 5]);
            z = b2iu(aa[j + 1]) * 8 + b2iu(aa[j + 2]) * 4 + b2iu(aa[j + 3]) * 2 + b2iu(aa[j + 4]);
            ss[i] = iu2b(ccom_SSS_p[i][y][z]);
            y = 3;
            for (k = 0; k < 4; k++) {
                bb[m++] = iu2b((b2iu(ss[i]) >>> y) & 1);
                y--;
            }

        }
    }

    private void FF(int n, byte[] ll, byte[] rr, byte[] LL, byte[] RR) {
        int i;
        byte[] buffer = new byte[64], tmp = new byte[64];
        for (i = 0; i < 48; i++)
            buffer[i] = rr[e_r_p[i] - 1];
        for (i = 0; i < 48; i++)
            buffer[i] = iu2b((b2iu(buffer[i]) + b2iu(K[n][i])) & 1);

        Fs_box(buffer, tmp);

        for (i = 0; i < 32; i++)
            buffer[i] = tmp[local_PP[i] - 1];

        for (i = 0; i < 32; i++)
            RR[i] = iu2b((b2iu(buffer[i]) + b2iu(ll[i])) & 1);

        for (i = 0; i < 32; i++)
            LL[i] = rr[i];
    }

    private void _Fiip(byte[] text, byte[] ll, byte[] rr) {
        int i;
        byte[] tmp = new byte[64];
        for (i = 0; i < 32; i++)
            tmp[i] = ll[i];
        for (i = 32; i < 64; i++)
            tmp[i] = rr[i - 32];
        for (i = 0; i < 64; i++)
            text[i] = tmp[_iip_tab_p[i] - 1];
    }

    /*
    private void Fcompress016(byte[] out, byte[] in) {
        int times;
        int i, j;

        for (i = 0; i < 16; i++) {
            times = 3;
            in[i] = 0;
            for (j = 0; j < 4; j++) {
                in[i] = iu2b(b2iu(in[i]) + (b2iu(out[i * 16 + j]) << times));
                times--;
            }
        }
    }
    */


    private void Fcompress0(byte[] out, byte[] in) {
        int times;
        int i, j;

        for (i = 0; i < 8; i++) {
            times = 7;
            in[i] = 0;
            for (j = 0; j < 8; j++) {
                in[i] = iu2b(b2iu(in[i]) + (b2iu(out[i * 8 + j]) << times));
                times--;
            }
        }
    }

    private void Fencrypt0(byte[] text, byte[] mtext) {
        byte[] ll = new byte[64], rr = new byte[64], LL = new byte[64], RR = new byte[64];
        byte[] tmp = new byte[64];
        int i, j;
        Fiip(text, ll, rr);

        for (i = 1; i < 17; i++) {
            FF(i, ll, rr, LL, RR);
            for (j = 0; j < 32; j++) {
                ll[j] = LL[j];
                rr[j] = RR[j];
            }
        }

        _Fiip(tmp, rr, ll);

        Fcompress0(tmp, mtext);
    }

    private void FDES(byte[] key, byte[] text, byte[] mtext) {
        byte[] tmp = new byte[64];
        Fexpand0(key, tmp);
        Fsetkeystar(tmp);
        Fencrypt0(text, mtext);
    }

    /* 加密 */
    public int ENCRYPT(byte[] key, byte[] s, byte[] d, int len) {
        int i, j;
        byte[] cData = new byte[8];
        byte[] cEncryptData = new byte[8];
        for (i = 0; i < len; i += 8) {
            if ((i + 8) > len) {
                desMemcpy(cData, s, 0, i, len - i);
                for (j = len - i; j < 8; j++)
                    cData[j] = 0;
            } else
                desMemcpy(cData, s, 0, i, 8);
            FDES(key, cData, cEncryptData);
            desMemcpy(d, cEncryptData, i, 0, 8);

        }
        return i;
    }

    private void Fdiscrypt0(byte[] mtext, byte[] text) {
        byte[] ll = new byte[64], rr = new byte[64], LL = new byte[64], RR = new byte[64];
        byte[] tmp = new byte[64];
        int i, j;
        Fiip(mtext, ll, rr);

        for (i = 16; i > 0; i--) {
            FF(i, ll, rr, LL, RR);
            for (j = 0; j < 32; j++) {
                ll[j] = LL[j];
                rr[j] = RR[j];
            }
        }

        _Fiip(tmp, rr, ll);

        Fcompress0(tmp, text);
    }

    /***************************************************************************
     * function: DES parameter: u_char * key ; key for encrypt u_char * mtext ;
     * encipher data u_char * text ; plain data return: none
     **************************************************************************/
    private void _FDES(byte[] key, byte[] mtext, byte[] text) {
        byte[] tmp = new byte[64];
        Fexpand0(key, tmp);
        Fsetkeystar(tmp);
        Fdiscrypt0(mtext, text);
    }

    /* 解密 */
    public int DECRYPT(byte[] key, byte[] s, byte[] d, int len) {
        int i;
        byte[] cData = new byte[8];
        byte[] cEncryptData = new byte[8];
        for (i = 0; i < len; i += 8) {
            desMemcpy(cEncryptData, d, 0, i, 8);
            _FDES(key, cEncryptData, cData);
            desMemcpy(s, cData, i, 0, 8);
        }
        return i;
    }

    public static byte[] hexStr2ByteArr(String strIn) {
        byte[] arrB = strIn.getBytes();
        int iLen = arrB.length;

        // 两个字符表示一个字节,所以字节数组长度是字符串长度除以2
        byte[] arrOut = new byte[iLen / 2];
        for (int i = 0; i < iLen; i = i + 2) {
            String strTmp = new String(arrB, i, 2);
            arrOut[i / 2] = (byte) Integer.parseInt(strTmp, 16);
        }
        return arrOut;
    }




    public String Encode(String str) {
        int i1;

        String digestHexStr;
        byte[] byte2 = new byte[3000];
        byte[] byte1 = str.getBytes();

        i1 = ENCRYPT(strKey.getBytes(), byte1, byte2, byte1.length);
        digestHexStr = "";
        for (int i = 0; i < i1; i++) {
            digestHexStr += byteHEX(byte2[i]);
        }

        return digestHexStr;
    }

    public String Decode(String str) {
        int i2;

        byte[] byteMingW = new byte[3000]; // 密文
        byte[] byteMiW = new byte[3000];

        byteMiW = hexStr2ByteArr(str);

        i2 = this.DECRYPT(this.strKey.getBytes(), byteMingW, byteMiW, byteMiW.length);

        // BASE64Encoder base64encoder = new BASE64Encoder();
        return new String(byteMingW, 0, i2).replaceAll(new String(new byte[]{0}), "").trim();
    }



    public static void main(String args[]) {
        String key = "msd12345";
        DES m = new DES(key);
        String tmp = m.Encode("oracle");
        String result = m.Decode("649813F067FA3E17");
        System.out.println("加密:"+tmp);
        System.out.println("解密:"+result);
    }
}

main方法执行结果:
DES通用加密解密类