WinSocket编程笔记（三）

二.Kerberos协议的实现

现有Alice、AS、TGS、Bob，实现Alice和Bob的安全密钥交换

这里只实现Alice和AS之间的通信

我把各个部分的代码拆开来写：

1.随机会话密钥生成

#include<iostream>
#include<stdlib.h>
using namespace std;

int main()
{   srand((unsigned)time(NULL));
    int key=(rand()%9000+1000);
    cout << key << endl;
    return 0;
}

2.加密算法

#include <iostream>
#include <cstring>
using namespace std;

int main()
{   string plain="ada54ff89m";
    string cipher="";
    int key=89696;
    int offset = key % 26;
    for(int i = 0; i < plain.length(); i++)
    {   char c = plain[i];
        if(isalpha(c))
        {
            if(c >= 'a' && c <= 'z')
            {
                c = 'a' + ((c - 'a' + offset) % 26);
                cipher += c;
        }
        else
        {
                c = 'A' + ((c - 'A' + offset) % 26);
                cipher += c;
        }}

        else if(isdigit(c))
            {
                c = '0' + ((c - '0' + offset) % 10);
                cipher += c;
            }
            else
            {
                cipher += c;
            }
    }
    cout<<cipher<<endl;
    }

3.解密算法

#include <iostream>
#include<cstring>
using namespace std;

int main()
{   int key=89659;
    string plain ="";
    string cipher="wsw0lmm";
    int offset = key % 26;
    for(int i = 0; i < cipher.length(); i++)
    {
        char c = cipher[i];
        if(isalpha(c))
        {
            if(c >= 'a' && c <= 'z')
            {
                c = 'z' - (('z' - c + offset) % 26);
                plain += c;
            }
            else
            {
                c = 'Z' - (('Z' - c + offset) % 26);
                plain += c;
            }
        }
        else if(isdigit(c))
            {
                c = '9' - (('9' - c + offset) % 10);
                plain += c;
            }
            else
            {
                plain += c;
            }
    }
    cout<<plain<<endl;
}

4.map属性读取内容（对应主密钥）//后来实际操作的时候还是定义了map<string,string>，省去了int转string

#include <fstream>
#include <string>
#include <iostream>
#include<map>
using namespace std;

int main()
{
    map<string,int> userHash;
    userHash["ALICE"]=12345;
    userHash["BOB"]=23456;
    userHash["AS"]=34567;
    userHash["TGS"]=45678;
    int TGSkey = userHash.find("TGS")->second;
    cout<<TGSkey<<endl;
    return 0;
}

然后就是结合之前的服务器代码，修改合并，之间好几次又要做到类型转换，否则会出错

服务器端主要代码：

    if(*a==*secret)//存储空间位置不同，不能直接比较，验证ALICE主密钥是否和发来的密钥相同
    {   cout<<"验证成功"<<endl;
        //AS主密钥加密ALICE用户名和随机会话密钥
        //int转string，KSkey -> KKSkey
        char t[256];
        string KKSkey;
        sprintf(t, "%d", KSkey);
        KKSkey = t;
        cout<<"KSkey:"<<KKSkey<<endl;
        string plain=name+KKSkey;
        cout<<"明文:"<<plain<<endl;
        string cipher="";
        int offset = 34567 % 26;
        for(int i = 0; i < plain.length(); i++)
        {   char c = plain[i];
            if(isalpha(c))
            {
                if(c >= 'a' && c <= 'z')
                {
                    c = 'a' + ((c - 'a' + offset) % 26);
                    cipher += c;
            }
            else
            {
                    c = 'A' + ((c - 'A' + offset) % 26);
                    cipher += c;
            }}

            else if(isdigit(c))
                {
                    c = '0' + ((c - '0' + offset) % 10);
                    cipher += c;
                }
                else
                {
                    cipher += c;
                }
        }
        //string转char,cipher -> p
        char p[100];
        int i;
        for( i=0;i<cipher.length();i++)
        {
            p[i] = cipher[i];
        }
        p[i] = '';
        cout<<"密文TGT:"<<p<<endl;
        //ALICE主密钥加密随机会话密钥
        string plain2=KKSkey;
        string cipherr="";
        int offset2 = 12345 % 26;
        for(int i = 0; i < plain2.length(); i++)
        {   char c2 = plain2[i];
            if(isalpha(c2))
            {
                if(c2 >= 'a' && c2 <= 'z')
                {
                    c2 = 'a' + ((c2 - 'a' + offset2) % 26);
                    cipherr += c2;
            }
            else
            {
                    c2 = 'A' + ((c2 - 'A' + offset2) % 26);
                    cipherr += c2;
            }}

            else if(isdigit(c2))
                {
                    c2 = '0' + ((c2 - '0' + offset2) % 10);
                    cipherr += c2;
                }
                else
                {
                    cipherr += c2;
                }
        }
        //string转char,cipherr -> p2
        char p2[100];
        int i2;
        for( i2=0;i2<cipherr.length();i2++)
        {
            p2[i2] = cipherr[i2];
        }
        p2[i2] = '';
        cout<<"ALICE主密钥加密的KSkey:"<<p2<<endl;
        //ALICE主密钥加密TGT
        string plain3=cipher;
        string cipherrr="";
        int offset3 = 12345 % 26;
        for(int i3 = 0; i3 < plain3.length(); i3++)
        {   char c3 = plain3[i3];
            if(isalpha(c3))
            {
                if(c3 >= 'a' && c3 <= 'z')
                {
                    c3 = 'a' + ((c3 - 'a' + offset3) % 26);
                    cipherrr += c3;
            }
            else
            {
                    c3 = 'A' + ((c3 - 'A' + offset3) % 26);
                    cipherrr += c3;
            }}

            else if(isdigit(c3))
                {
                    c3 = '0' + ((c3 - '0' + offset3) % 10);
                    cipherrr += c3;
                }
                else
                {
                    cipherrr += c3;
                }
        }
        //string转char,cipherrr -> p3
        char p3[100];
        int i4;
        for( i4=0;i4<cipherrr.length();i4++)
        {
            p3[i4] = cipherrr[i4];
        }
        p3[i4] = '';
        cout<<"ALICE主密钥加密以后的TGT:"<<p3<<endl;
    }

客户端代码基本上没有变化，这里就不贴上了

运行结果（因为不是同一次运行截图，所以结果不一样）：

服务器端：

客户端：

收到信息：

（待续）