import java.util.ArrayList;  import java.util.Iterator;  import java.util.Scanner;    public class DES {        public static void main(String[] args) {            String k = "0111000 0 0011100 0 1001101 0 1110110 0 0111011 0 1001001 0 1000010 0 1101101 0";          k = k.replaceAll(" ", "");          System.out.print("请输入要加密的明文：");          Scanner scn = new Scanner(System.in);          System.out.println("密文为："+getCode(scn.next(),k));        }        //将ArrayList中的字符串加密      public static String getCode(String s,String k) {          ArrayList<String> al = strToBinary(s);          String str = "";          for(Iterator<String> it = al.iterator(); it.hasNext();) {              str += encry(it.next(),k);          }            return str;      }        //将字符串的每四位转化成二进制代码存放在ArrayList中      public static ArrayList<String> strToBinary(String s) {          ArrayList<String> al = new ArrayList<String>();          String temp = "";          byte[] buf = s.getBytes();          for(int i = 0 ; i < buf.length;) {              temp += byteToBit(buf[i++]);              if(temp.length() == 64) {                  al.add(temp);                  temp = "";              }else if(i == buf.length && temp.length() < 64) {                  while(temp.length() < 64) {temp = "0"+temp;}                  al.add(temp);              }            }            return al;      }        //将每个byte转化成8个二进制位      public static String byteToBit(byte b) {          String s = Integer.toBinaryString(b);          while(s.length() < 8) {s = "0"+s;}          return s;      }        //初始置换IP表      final static int[][] initIP = {{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}};      //密钥置换表      final static int[][] keyPermu = {{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}};      //每轮循环左移的位数表      final static int[] moveBit = {1,1,2,2,2,2,2,2,1,2,2,2,2,2,2,1};      //压缩置换表      final static int[][] compressPermu = {{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}};      //扩展变换表      final static int[][] extendPermu = {{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}};      //8个S盒      final static int[][] sBox1 = {{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}};        final static int[][] sBox2 = {{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},                                     {0,14,4,11,10,4,13,1,5,8,12,6,9,3,2,15},                                     {13,8,10,1,3,15,4,2,11,6,7,12,0,5,14,9}};        final static int[][] sBox3 = {{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},                                     {3,6,4,9,8,15,3,0,11,1,2,12,5,10,14,7},                                     {1,10,13,0,6,9,8,7,4,15,14,3,11,5,2,12}};        final static int[][] sBox4 = {{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}};        final static int[][] sBox5 = {{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}};        final static int[][] sBox6 = {{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}};        final static int[][] sBox7 = {{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}};        final static int[][] sBox8 = {{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}};        //P——盒转换表      final static int[][] pBox = {{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}};      //末尾置换IP逆表      final static int[][] endIPpermu = {{40,8,18,16,56,24,64,32,39,7,47,15,55,23,63,31},                                          {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}};        //初始置换，IP置换      public static String initPermu(String s) {          StringBuilder sb = new StringBuilder();          for(int i = 0; i < initIP.length; i++) {              for(int j = 0; j < initIP[i].length; j++) {                  sb.append(s.charAt(initIP[i][j]-1));              }          }            return sb.toString();      }        //密钥转换      public static String keyPermu(String s) {            StringBuilder sb = new StringBuilder();            for(int i = 0; i < keyPermu.length; i++) {              for(int j = 0; j < keyPermu[i].length; j++) {                  sb.append(s.charAt(keyPermu[i][j]-1));              }          }            return sb.toString();             }        public static String keyMove(String key,int times) {          int bit = moveBit[times-1];            int l = key.length();          String pre = key.substring(0, l/2);          String bef = key.substring(l/2, l);          //密钥移位          pre = pre.substring(bit)+pre.substring(0, bit);          bef = bef.substring(bit)+bef.substring(0, bit);            return pre+bef;        }        //压缩置换，从56位密钥中选出48位作为当前加密的轮密钥      public static String compressPermu(String s) {          StringBuilder sb = new StringBuilder();            for(int i = 0; i < compressPermu.length; i++) {              for(int j = 0; j < compressPermu[i].length; j++) {                  sb.append(s.charAt(compressPermu[i][j]-1));              }          }            return sb.toString();      }        //扩展变换，得到的是明文后32位经扩展后的48位      public static String expanPermu(String s) {          StringBuilder sb = new StringBuilder();          //s = s.substring(s.length()/2);          for(int i = 0; i < extendPermu.length; i++) {              for(int j = 0; j < extendPermu[i].length; j++) {                  sb.append(s.charAt(extendPermu[i][j]-1));              }          }          return sb.toString();      }        //两个字符串异或      public static String getXor(String s,String k) {          StringBuilder sb = new StringBuilder();          for(int i = 0; i < s.length() && i < k.length(); i++) {              if(s.charAt(i) == k.charAt(i))                  sb.append('0');              else                  sb.append('1');          }          return sb.toString();      }        //S——盒替代      public static String sBoxSub(String s) {            String s1 = s.substring(0, 6);   int a1 = getValue(s1,sBox1);          String s2 = s.substring(6, 12);  int a2 = getValue(s2,sBox2);          String s3 = s.substring(12,18);  int a3 = getValue(s3,sBox3);          String s4 = s.substring(18,24);  int a4 = getValue(s4,sBox4);          String s5 = s.substring(24,30);  int a5 = getValue(s5,sBox5);          String s6 = s.substring(30,36);  int a6 = getValue(s6,sBox6);          String s7 = s.substring(36, 42); int a7 = getValue(s7,sBox7);          String s8 = s.substring(42, 48); int a8 = getValue(s8,sBox8);            return getBinary(a1)+getBinary(a2)+getBinary(a3)+getBinary(a4)+                  getBinary(a5)+getBinary(a6)+getBinary(a7)+getBinary(a8);      }        //将从sBox中得到的16进制数转换成二进制       public static String getBinary(int a) {          String bin = Integer.toBinaryString(a);          while(bin.length() < 4) {bin = "0" + bin;}            return bin;      }        //根据六位二进制代码得到      public static int getValue(String str,int[][] sBox) {          String s1 = str.charAt(0)+""+str.charAt(str.length()-1);           int a1 = Integer.parseInt(s1, 2);            String s2 = str.substring(1, 5);           int a2 = Integer.parseInt(s2, 2);          //得到sBox中的16进制数          int value = sBox[a1][a2];            return value;      }        //P——盒置换      public static String pBoxPermu(String s) {          StringBuilder sb = new StringBuilder();          for(int i = 0; i < pBox.length; i++) {              for(int j = 0; j < pBox[i].length; j++) {                  sb.append(s.charAt(pBox[i][j]-1));              }          }            return sb.toString();      }        //末尾置换IP逆      public static String inverseInitPermu(String s) {          StringBuilder sb = new StringBuilder();          for(int i = 0; i < endIPpermu.length; i++) {              for(int j = 0; j < endIPpermu[i].length; j++) {                  sb.append(s.charAt(endIPpermu[i][j]-1));              }          }          return sb.toString();      }        //中间加密过程      public static String midEncry(String s,String k) {          String str = "";            String sLeft = s.substring(0, s.length()/2);  //s的左32位            String sRight = s.substring(s.length()/2,s.length()); //s的右32位            String sRigExtend = expanPermu(sRight);//s的右半部分扩展到48位            String xor = "";          xor = getXor(sRigExtend,k); //与k异或            str = sBoxSub(xor);//结过8个s盒            str = pBoxPermu(str); // 经过p盒置换            str = getXor(sLeft,str); //与s的左半部分异或得到这轮输出的右半部分,s的右半部分作输出的左半部分            return sRight + str;        }        //加密过程      public static String encry(String plaintext,String key) {          String ciphertext = "";          String k = keyPermu(key);//置换,得到56位            //1.明文经过IP置换后          ciphertext = initPermu(plaintext);            for(int times = 1; times < 17; times++) {                k = keyMove(k,times);              key = compressPermu(k);                   //2.中间加密过程              ciphertext = midEncry(ciphertext,key);            }            //3.末尾置换          ciphertext = inverseInitPermu(ciphertext);            return ciphertext;      }    }