DES的代码，因为是用QT写的。所以说直接复制粘贴是不能运行的啊。

/*This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.*/

#ifndef DES_H
#define DES_H

#include <QObject>
#define Key unsigned char
#define Data unsigned int
class DES : public QObject
{
    Q_OBJECT
private:
    Key myKey[8];
    Key subkeyList[16][6];
    Data data[2];
    unsigned int f;
public:
    explicit DES(QObject *parent = 0);
    void creatRandomKey();
    void creatSubkey();
    void setKey()
    void setData(Data data0,Data data1){data[0]=data0;data[1]=data1;}
    void IP();
    void IPInv();
    void crypt(int no);
    void swap(){std::swap(data[0],data[1]);}
    template <typename T>
    void printb(T t[],int num,char *str = NULL);


    unsigned char getbit(Key key[],int num){return ((key[num/8]>>(7-num%8)) & 1);}
    void putbit(Key key[],int num,unsigned char bit){key[num/8] |= (bit<<(7-num%8));}
signals:
public slots:
};

#endif // DES_H

#include "des.h"
#include <memory>
#include <iostream>
#include <cstdlib>
#include <ctime>
#include <cstdlib>
DES::DES(QObject *parent) :
    QObject(parent)
{
}
void DES::creatRandomKey(){
    srand(time(NULL));
    for(int i=0;i<8;++i)
        myKey[i] = (rand()%128)<<1;
    //忽略奇偶校验位
    std::cout<<"KEY:";
    for (int i=0;i<8;++i)
        std::cout<<(int)myKey[i]<<" ";
    std::cout<<std::endl;
}//creatRamdinKey
void DES::creatSubkey(){
    unsigned char pc_1[56]={//PC-1置换。
           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};
    unsigned char pc_2[48]={//PC-2置换。
           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};

    Key cKey[4] = {0};
    Key dKey[4] = {0};
    for (int i=0;i<56;++i){
        (i<28)?
                    putbit(cKey,i,getbit(myKey,pc_1[i]-1)):
                    putbit(dKey,i-28,getbit(myKey,pc_1[i]-1));
    }
    unsigned char movebit[16]={//循环移位表。
            1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};
    for (int i=0;i<16;++i){//十六轮
        for (int j=1;j<=movebit[i];++j){
            Key tcKey[4]={0},tdKey[4]={0};
            for (int k=28;k>0;--k){
                putbit(tcKey,k-1,getbit(cKey,k%28));
                putbit(tdKey,k-1,getbit(dKey,k%28));
            }
            memcpy(cKey,tcKey,4*sizeof(Key));
            memcpy(dKey,tdKey,4*sizeof(Key));
        }//循环左移
        Key combineKey[56/8]={0};
        for(int k=0;k<56;++k){
            (k<28)?
                        putbit(combineKey,k,getbit(cKey,k)):
                        putbit(combineKey,k,getbit(dKey,k-28));
        }
        memset(subkeyList[i],0,sizeof(Key)*6);
        for(int l=0;l<48;++l){
            putbit(subkeyList[i],l,getbit(combineKey,pc_2[l]-1));
        }
    }
};//CreatKey
void DES::IP(){
    unsigned char ip[64]={IP置换。
            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 };
    Data tdata[2] = {0};
    for (int i=0;i<64;++i)
        tdata[i/32] |= (((data[(ip[i]-1)/32]>>(31-(ip[i]-1)%32))&1)<<(31-i%32));
    memcpy(data,tdata,sizeof(Data)*2);
};//IP
void DES::IPInv(){
    unsigned char ip_1[64]={//IP-1置换。可根据IP表生成
            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 };
    Data tdata[2] = {0};
    for (int i=0;i<64;++i)
        tdata[i/32] |= (((data[(ip_1[i]-1)/32]>>(31-(ip_1[i]-1)%32))&1)<<(31-i%32));
    memcpy(data,tdata,sizeof(Data)*2);
    std::cout<<data[0]<<" "<<data[1]<<std::endl;
};//IPInv
void DES::crypt(int no){
    //EXPAND
    //printb(data,2,"BEFOR:");
    Key expandOfA[8] = {0};
    Key expandOfK[8] = {0};
    unsigned char e[48] ={//E扩展
            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};
    for (int i=0;i<48;++i)
        expandOfA[i/6]|=((data[1]>>(32-e[i]))&1)<<(7-i%6);
    //printb(&data[1],1,"data:");
    //printb(expandOfA,8,"expand:\t");
    for (int i=0;i<48;++i)
        expandOfK[i/6]|=(subkeyList[no][i/8]>>(7-i%8))<<(7-i%6);
    //printb(subkeyList[no],6,"subkey:");
    //printb(expandOfK,8,"expand:\t");
    Key b[8] = {0};
    for (int i=0;i<8;++i)
        b[i] = expandOfA[i] ^ expandOfK[i];
    //printb(b,8,"b:\t");
    unsigned char s[8][4][16] =
            {{//S盒1
             {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盒2
             {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盒3
             {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盒4
             {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盒5
              {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盒6
             {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盒7
             {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盒8
             {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}}};
    unsigned int combineInt = 0;
    for (int i=0;i<8;++i){
        int line,row;
        line = (((b[i]>>7)&1)<<1)|((b[i]>>2)&1);
        row = (b[i]>>3) & 0xF;
        //std::cout<<"line:"<<line<<" row:"<<row<<" s:"<<(int)s[i][line][row]<<std::endl;
        combineInt<<=4;
        combineInt |= s[i][line][row];
        //printb(&s[i][line][row],1);
        //printb(&combineInt,1);
    }
    unsigned char p[32]={//P置换。
           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 };
    f = 0;
    for (int i=0;i<32;++i){
        f <<= 1;
        f |=((combineInt>>(32-p[i]))&1);
    }
    //printb(&combineInt,1);
    //printb(&f,1,"f:");
    data[1] = data[1];
    data[0] = data[0] ^ f;
    //printb(data,2,"AFTER:");
}

template <typename T>
void DES::printb(T t[],int num,char* str)
{
    int i,j;
    if (str) std::cout<<str;
    for (i=0;i<num;++i){
        for(j=sizeof(T)*8-1;j>=0;--j)
            std::cout<<(t[i]>>j & 1);
        std::cout<<" ";
    }
    std::cout<<std::endl;
};

#include <QtCore/QCoreApplication>
#include "des.h"
#include <iostream>
#define N 16
int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    DES des;
    des.creatRandomKey();
    des.creatSubkey();
    des.setData(4,4);
    int choice;
    std::cout<<"Encrypt(0) or Decrypt(1):";
    std::cin>>choice;
    if (choice = 0)
    {
        des.IP();
        for (int i=0;i<N-1;i++){
            des.crypt(i);
            des.swap();
        }
        des.crypt(N-1);
        des.IPInv();
    }
    else{
        des.IP();
        for (int i=N-1;i>0;i--){
            des.crypt(i);
            des.swap();
        }
        des.crypt(0);
        des.IPInv();
    }
    return a.exec();
}