单表置换密码的C++代码实现

1、#include<iostream>#include<string>#include<fstream>using namespace std;ifstream in("密码学.txt");void JiaMi(char ZhiHuan); /加密函数void JieMi(char ZhiHuan); /解密函数void setZhiHuan(char ZhiHuan,char fanZhiHuanBiao); /设置置换表函数int main()int m; /确定是加密或解密？加密为1，解密为2char ZhiHuanBiao'

2、z'+1; /正向置换表，加密时用char fanZhiHuanBiao'Z'+1; /反向置换表，解密时用cout<<"加密按输入1，解密输入2"<<endl;in>>m; /读入msetZhiHuan(ZhiHuanBiao, fanZhiHuanBiao); /设置置换表switch(m) /判断m值，执行相应的功能case 1: JiaMi(ZhiHuanBiao);break;case 2: JieMi(fanZhiHuanBiao);break;default:break;return 0;void J

3、iaMi(char ZhiHuan) /加密string MingWen; /保存明文cout<<endl<<"请输入明文："getline(in,MingWen); /读入明文cout<<MingWen<<endl; cout<<"加密后的密文为："<<endl;for(int i=0; i<MingWen.length(); i+) /直接利用置换表输出密文if(MingWeni>='a' && MingWeni<='z&

4、#39;)cout<<ZhiHuan MingWeni ;else cout<<MingWeni;cout<<endl;void JieMi(char fanZhiHuan)string MiWen; /保存密文cout<<endl<<"请输入密文："getline(in,MiWen); /读入密文cout<<MiWen<<endl;cout<<"解密后的明文为："<<endl;for(int i=0; i<MiWen.length(); i

5、+) /直接利用反置换表输出明文if(MiWeni>='A' && MiWeni<='Z')cout<<fanZhiHuan MiWeni ;else cout<<MiWeni;cout<<endl;void setZhiHuan(char ZhiHuanBiao,char fanZhiHuanBiao)int i; /i和j是循环变量，除此之外没有任何意义char j;string s; /密钥cout<<"请输入密钥（大写）："getline(in,s); /读入

6、密钥cout<<s<<endl; /输出密钥cout<<"置换表为："<<endl;string s1; for(i = 0 ; i < s.length();i+) /对密钥进行处理（去掉空格和重复的字符）bool sign =0; /标志变量if(si >= 'A' && si <='Z')for(int j = 0; j < s1.length();j+)if(si = s1j)sign = 1;break;if(sign = 0) s1 = s1

7、+ si;else sign = 0;for( j ='a'j<='z'j+)cout<<j<<" "cout<<endl; /输出小写字母 从a到zchar ch='A'for( i = 'a' ;i <= 'z' i+) /该循环利用密钥得到置换表if(i < 'a' + s1.length() /前面直接用s1代替 ZhiHuanBiaoi = s1i-'a' else /后面将剩下的"贴"上去for(int j = 'a' j < 'a' + s1.length(); j+)if(ch = ZhiHuanBiaoj)ch+;j= 'a' /每次都从头开始搜索continue;ZhiHuanBiaoi = ch; ch+;cout<<ZhiHuanBiaoi<<" " /同时输出置换表cout<<endl;for( i='a' i<= 'z' i+) /该循环利用置换表得到反置换表fanZhiHuanBiao ZhiHua