古典加密算法⽂档及代码信息安全程序设计⼀⼀、实验⽬的：学习并掌握密码学基础中古典加密体制的⼀些主要⽅法。
⼆、设计要求：编程实现移位密码、仿射密码、维吉尼亚密码和置换密码，要求如下：1、程序输⼊为明⽂和密钥（对于仿射密码应该检查密钥的合法性）；2、执⾏加密和解密过程；3、输出加密的密⽂和解密恢复的明⽂，并和开始输⼊的明⽂进⾏⽐较。
三、设计步骤：程序在JA V A环境中实现，由于编程基础不够扎实可能程序没有明显的体现出⾯向对象的风格，期望⽼师见谅。
1：⾸先构造基本的古典加密界⾯2：然后添加界⾯所⽤到的组件和注册监听器。
3：编写各个算法的加密和解密函数进⾏加密解密时的调⽤。
四、以下分别是构造界⾯，添加组件及监听器和各个算法实现代码，分别都有标注import java.awt.*;import javax.swing.*;import java.awt.event.*;/*构造古典加密算法界⾯*/public class JMJM extends WindowAdapter implements ActionListener,ItemListener{Label l1=new Label("输⼊:"),l2=new Label("加密:"),l3=new Label("解密:"),l4=new Label("密钥:");JFrame f;TextField t1=new TextField(55),t2=new TextField(55),t3=new TextField(55),t4=new TextField(20);Button b1=new Button("加密"),b2=new Button("解密"),b3=new Button("清屏");Choice c1;Panel p1,p2,p3,p4,p5,p6,p7,p8,p9;public void display(){f=new JFrame("加密算法");f.setSize(480,200);f.setLocation(200,140);f.setBackground(Color.lightGray);f.setLayout(new BorderLayout());tiajiazujian();f.setV isible(true);}/*添加界⾯组件以及监听器*/public void tiajiazujian(){c1=new Choice();c1.add("移位算法");c1.add("仿射算法");c1.add("维吉尼亚算法");c1.add("置换算法"); c1.addItemListener(this);f.add(c1,"North");p1=new Panel();p3=new Panel();f.add(p3,"Center");p3.setLayout(new FlowLayout());p3.add(l1);p3.add(t1);p3.add(l2);p3.add(t2);p3.add(l3);p3.add(t3);p2=new Panel();f.add(p2,"South");p2.setLayout(new GridLayout(1,5));p2.add(l4);p2.add(t4);p2.add(b1);p2.add(b2);p2.add(b3);b1.addActionListener(this);b2.addActionListener(this);b3.addActionListener(this);}/*对应不同加密算法的按钮点击事件*/public void actionPerformed(ActionEvent e){if (e.getSource()==b3&&c1.getSelectedIndex()==0){t1.setText(" ");t2.setText(" ");t3.setText(" ");}if (e.getSource()==b1&&c1.getSelectedIndex()==0){ywjiami();}if(e.getSource()==b2&&c1.getSelectedIndex()==0){ywjiemi();}if(e.getSource()==b1&&c1.getSelectedIndex()==1){fcjiami();}if(e.getSource()==b2&&c1.getSelectedIndex()==1){fcjiemi();}if(e.getSource()==b1&&c1.getSelectedIndex()==2){ wjnyjiami();}if(e.getSource()==b2&&c1.getSelectedIndex()==2){ wjnyjiemi();}if(e.getSource()==b1&&c1.getSelectedIndex()==3){ zhjiami();}if(e.getSource()==b2&&c1.getSelectedIndex()==3){ zhjiemi();}}public void itemStateChanged(ItemEvent e){}/*移位加密算法*/public void ywjiami(){String s1;String s2;char zifu[];s1=t1.getText();s2=t4.getText();int a;a=Integer.parseInt(s2);zifu = s1.toCharArray();for (int i = 0;i{zifu[i]=(char)(((zifu[i]-97+a)%26)+97);}String s3=new String(zifu);s3=s3.toUpperCase();t2.setText(s3);}/*移位解密算法*/public void ywjiemi(){String s1;String s2;char zifu[];s1=t2.getText();s2=t4.getText();int a;a=Integer.parseInt(s2);zifu = s1.toCharArray();for (int i = 0;i{zifu[i]=(char)(((zifu[i]-97-a)%26)+97); }String s3=new String(zifu);s3=s3.toLowerCase();t3.setText(s3);}/*求最⼤公约数－辗转相除法*/int gcd(int a, int b){int k = 0;do{k = a%b;a = b;b = k;}while(k!=0);return a;}/*求模逆*/int Ni(int a, int b){int i = 0;while(a*(++i)%b!=1);return i;}/*仿射加密算法*/public void fcjiami(){int i=0, a=0, b=0, tmp;String s1;String s2;char zifu[];s1=t1.getText();s2=t4.getText();a=Integer.parseInt(s2)/10;b=Integer.parseInt(s2)%10;zifu = s1.toCharArray();/*如果输⼊密钥不合法则显⽰密钥错误*/ if(gcd(a,26)!=1) {String s3=new String();s3="密钥错误";t3.setText(s3);}for(i=0; i{if(zifu[i]>96&&zifu[i]<123)zifu[i] = (char)((a*(zifu[i]-97)+b)%26+65);else if(zifu[i]>64&&zifu[i]<91)zifu[i] = (char)((a*(zifu[i]-65)+b)%26+65);}String s4=new String(zifu);t2.setText(s4);}/*仿射解密算法*/public void fcjiemi(){int i=0, a=0, b=0, tmp;String s1;String s2;char zifu[];s1=t1.getText();s2=t4.getText();/*在密钥输⼊⽂本框中输⼊2位密钥⾸先转换成2位整数在利⽤‘/’和‘％’算法求出2个合法密钥在进⾏计算*/ a=Integer.parseInt(s2)/10;b=Integer.parseInt(s2)%10;zifu = s1.toCharArray();for(i=0; i{if(zifu[i]>64&&zifu[i]<91){tmp = Ni(a,26)*((zifu[i]-65)-b);if(tmp<0)zifu[i] = (char)(tmp%26+26+97);elsezifu[i] = (char)(tmp%26+97);}}String s4=new String(zifu);t3.setText(s4);}/*维吉尼亚加密算法*/public void wjnyjiami(){int i,j,s=0;int k=0 ;String s1;String s2;char zifu[],miyao[];s1=t1.getText();s2=t4.getText();miyao =s2.toCharArray();zifu = s1.toCharArray();for(i=0; i{zifu[i] = (char)((zifu[i]-97+(miyao[k%miyao.length]-97))%26+97);k++;}String s3=new String(zifu);s3=s3.toUpperCase();t2.setText(s3);}/*维吉尼亚解密算法*/public void wjnyjiemi(){int i,j,k=0,tmp;String s1;String s2;char zifu[],miyao[];s1=t2.getText();s2=t4.getText();s1=s1.toLowerCase();miyao =s2.toCharArray();zifu = s1.toCharArray();/*解密算法中会出现减出负数的状况如果出现负数加26解决问题*/ for (i =0;i {tmp = (zifu[i]-miyao[k%(miyao.length)]);zifu[i]=(char)(tmp+65);if (tmp<0)zifu[i] =(char)(tmp+65+26);k++;};String s3=new String(zifu);s3=s3.toLowerCase();t3.setText(s3);}/*置换加密算法*/public void zhjiami(){int i,k=0,tmp;String s1;s1=t1.getText();s2=t4.getText();zifu=s1.toCharArray();miyao =s2.toCharArray();char zifu1[]=new char[zifu.length];int j[]=new int[miyao.length];/*将输⼊的密钥的ASC码减去字符0对应的ASC码得数相应密钥对应的整形数值存取在整型数组j中*/ for(i=0;ij[i]=miyao[i]-48;};for(i=0; i{tmp = i/miyao.length;zifu1[i] =zifu[j[i%miyao.length]+(tmp*miyao.length)-1];};String s3=new String(zifu1);s3=s3.toUpperCase();t2.setText(s3);}/*置换解密算法*/public void zhjiemi(){int i,k=0,tmp;String s1;String s2;char zifu[],miyao[];s1=t2.getText();s2=t4.getText();zifu=s1.toCharArray();miyao =s2.toCharArray();char zifu1[]=new char[zifu.length];int j[]=new int[miyao.length];/*将输⼊的密钥的ASC码减去字符0对应的ASC码得数相应密钥对应的整形数值存取在整型数组j中*/};for(i=0; itmp = i/miyao.length;zifu1[j[i%miyao.length]+tmp*miyao.length-1] =zifu[i];};String s3=new String(zifu1);s3=s3.toLowerCase();t3.setText(s3);}public static void main(String arg[]){JMJM ob=new JMJM();ob.display();}}总结：通过这次的编程作业对古典加密的四种算法从刚开始的⽣涩到现在的熟悉并且扎实的掌握了算法的原理，在编程中遇到很多问题，⼤部分都不是因为算法本⾝的原理，都是因为⾃⼰的编程基础不够扎实造成的，总会遇到许多问题耗时间去学习去处理，还⽋缺⾯向对象编程的思想，在整个程序中致使⾯向对象的特点不明显，也由于⾃⼰编程基础的不扎实造成完成作业的时间有点长，给⽼师批改作业带来的不便请您见谅！但是经过⽐较长的作业时间，遇到了许多困难并⼀点⼀点解决，在理解算法和编程技术⽅⾯我都有了⼀定提⾼，最后看到⾃⼰完成的作业有很⼤的欣慰，我会在以后的学习中更加注重密码学的学习和锻炼⾃⼰的编程能⼒提⾼⾃⼰的编程技术。
