descrypt.java

这是linux下ssl vpn的实现程序

        b[offset++] = (byte) ((iValue >>> 8) & 0xff);
        b[offset++] = (byte) ((iValue >>> 16) & 0xff);
        b[offset++] = (byte) ((iValue >>> 24) & 0xff);
    }

    private static final void PERM_OP(int a, int b, int n, int m, int results[]) {
        int t;

        t = ((a >>> n) ^ b) & m;
        a ^= t << n;
        b ^= t;

        results[0] = a;
        results[1] = b;
    }

    private static final int HPERM_OP(int a, int n, int m) {
        int t;

        t = ((a << (16 - n)) ^ a) & m;
        a = a ^ t ^ (t >>> (16 - n));

        return (a);
    }

    private static int[] des_set_key(byte key[]) {
        int schedule[] = new int[ITERATIONS * 2];

        int c = fourBytesToInt(key, 0);
        int d = fourBytesToInt(key, 4);

        int results[] = new int[2];

        PERM_OP(d, c, 4, 0x0f0f0f0f, results);
        d = results[0];
        c = results[1];

        c = HPERM_OP(c, -2, 0xcccc0000);
        d = HPERM_OP(d, -2, 0xcccc0000);

        PERM_OP(d, c, 1, 0x55555555, results);
        d = results[0];
        c = results[1];

        PERM_OP(c, d, 8, 0x00ff00ff, results);
        c = results[0];
        d = results[1];

        PERM_OP(d, c, 1, 0x55555555, results);
        d = results[0];
        c = results[1];

        d = (((d & 0x000000ff) << 16) | (d & 0x0000ff00) | ((d & 0x00ff0000) >>> 16) | ((c & 0xf0000000) >>> 4));
        c &= 0x0fffffff;

        int s, t;
        int j = 0;

        for (int i = 0; i < ITERATIONS; i++) {
            if (shifts2[i]) {
                c = (c >>> 2) | (c << 26);
                d = (d >>> 2) | (d << 26);
            } else {
                c = (c >>> 1) | (c << 27);
                d = (d >>> 1) | (d << 27);
            }

            c &= 0x0fffffff;
            d &= 0x0fffffff;

            s = skb[0][(c) & 0x3f] | skb[1][((c >>> 6) & 0x03) | ((c >>> 7) & 0x3c)]
                            | skb[2][((c >>> 13) & 0x0f) | ((c >>> 14) & 0x30)]
                            | skb[3][((c >>> 20) & 0x01) | ((c >>> 21) & 0x06) | ((c >>> 22) & 0x38)];

            t = skb[4][(d) & 0x3f] | skb[5][((d >>> 7) & 0x03) | ((d >>> 8) & 0x3c)] | skb[6][(d >>> 15) & 0x3f]
                            | skb[7][((d >>> 21) & 0x0f) | ((d >>> 22) & 0x30)];

            schedule[j++] = ((t << 16) | (s & 0x0000ffff)) & 0xffffffff;
            s = ((s >>> 16) | (t & 0xffff0000));

            s = (s << 4) | (s >>> 28);
            schedule[j++] = s & 0xffffffff;
        }
        return (schedule);
    }

    private static final int D_ENCRYPT(int L, int R, int S, int E0, int E1, int s[]) {
        int t, u, v;

        v = R ^ (R >>> 16);
        u = v & E0;
        v = v & E1;
        u = (u ^ (u << 16)) ^ R ^ s[S];
        t = (v ^ (v << 16)) ^ R ^ s[S + 1];
        t = (t >>> 4) | (t << 28);

        L ^= SPtrans[1][(t) & 0x3f] | SPtrans[3][(t >>> 8) & 0x3f] | SPtrans[5][(t >>> 16) & 0x3f] | SPtrans[7][(t >>> 24) & 0x3f]
                        | SPtrans[0][(u) & 0x3f] | SPtrans[2][(u >>> 8) & 0x3f] | SPtrans[4][(u >>> 16) & 0x3f]
                        | SPtrans[6][(u >>> 24) & 0x3f];

        return (L);
    }

    private static final int[] body(int schedule[], int Eswap0, int Eswap1) {
        int left = 0;
        int right = 0;
        int t = 0;

        for (int j = 0; j < 25; j++) {
            for (int i = 0; i < ITERATIONS * 2; i += 4) {
                left = D_ENCRYPT(left, right, i, Eswap0, Eswap1, schedule);
                right = D_ENCRYPT(right, left, i + 2, Eswap0, Eswap1, schedule);
            }
            t = left;
            left = right;
            right = t;
        }

        t = right;

        right = (left >>> 1) | (left << 31);
        left = (t >>> 1) | (t << 31);

        left &= 0xffffffff;
        right &= 0xffffffff;

        int results[] = new int[2];

        PERM_OP(right, left, 1, 0x55555555, results);
        right = results[0];
        left = results[1];

        PERM_OP(left, right, 8, 0x00ff00ff, results);
        left = results[0];
        right = results[1];

        PERM_OP(right, left, 2, 0x33333333, results);
        right = results[0];
        left = results[1];

        PERM_OP(left, right, 16, 0x0000ffff, results);
        left = results[0];
        right = results[1];

        PERM_OP(right, left, 4, 0x0f0f0f0f, results);
        right = results[0];
        left = results[1];

        int out[] = new int[2];

        out[0] = left;
        out[1] = right;

        return (out);
    }

    public static final String crypt(String salt, String original) {
        while (salt.length() < 2)
            salt += "A";

        StringBuffer buffer = new StringBuffer("             ");

        char charZero = salt.charAt(0);
        char charOne = salt.charAt(1);

        buffer.setCharAt(0, charZero);
        buffer.setCharAt(1, charOne);

        int Eswap0 = con_salt[(int) charZero];
        int Eswap1 = con_salt[(int) charOne] << 4;

        byte key[] = new byte[8];

        for (int i = 0; i < key.length; i++)
            key[i] = (byte) 0;

        for (int i = 0; i < key.length && i < original.length(); i++) {
            int iChar = (int) original.charAt(i);

            key[i] = (byte) (iChar << 1);
        }

        int schedule[] = des_set_key(key);
        int out[] = body(schedule, Eswap0, Eswap1);

        byte b[] = new byte[9];

        intToFourBytes(out[0], b, 0);
        intToFourBytes(out[1], b, 4);
        b[8] = 0;

        for (int i = 2, y = 0, u = 0x80; i < 13; i++) {
            for (int j = 0, c = 0; j < 6; j++) {
                c <<= 1;

                if (((int) b[y] & u) != 0)
                    c |= 1;

                u >>>= 1;

                if (u == 0) {
                    y++;
                    u = 0x80;
                }
                buffer.setCharAt(i, (char) cov_2char[c]);
            }
        }
        return (buffer.toString());
    }

    public static void main(String args[]) {
        if (args.length >= 2) {
            System.out.println("[" + args[0] + "] [" + args[1] + "] => [" + DESCrypt.crypt(args[0], args[1]) + "]");
        }
    }
}