caesar.java

来自「凯撒密码 Java版的 好像有些小毛病 帮我看看啊」· Java 代码 · 共 72 行

package ende;
 public class Caesar {

 /**
06 * 
07 * Contains two function of encrypt and decrypt of Caesar
08 * 
09 * 古典密码学体系中的凯撒密码的加密与解密函数
10 * 仅仅属于算法上的研究
11 * 
12 * @author soundofu
13 *
14 * @E-mail：[e-mail]
15 */
 
 //make a default dictionary of char string.
 static private String dictionary = "abcdefghijklmnopqrstuvwxyz";
 
 
 /*
22 * Function of encrypt
23 * 
24 * String encrypt(String strs, int key);
25 * 
26 */
 static String encrypt(String strs,int key)
 {
char [] encrypted = new char[strs.length()];
 
 int pos;
 for(int i=0;i<100;i++)
 {
 pos = dictionary.indexOf(strs.charAt(i));
 if(pos != -1)
 encrypted [i] = dictionary.charAt((pos+key)%dictionary.length());
 }
 return new String(encrypted);
 }
 
 
 /*
43 * Function of decrypt
44 * 
45 * String decrypt(String strs,int key);
46 * 
47 */
 static String decrypt(String strs,int key)
 {
 char [] clearchar = new char[strs.length()];
 int pos;
 for(int i=0;i<100;i++)
 {
 pos = dictionary.indexOf(strs.charAt(i));
 if(pos != -1)
 clearchar [i] = dictionary.charAt((pos-key+dictionary.length())%dictionary.length());
 }
 
 return new String(clearchar);
 }
 public static void main(String[] args) {
 
 
 String orignial = "ijkm"; //String to be encrypted
 
 //Get the encrypted(String,int) function.
 System.out.println(encrypt(orignial,8));
 
 //Get the decrypted(String,int) function.
 System.out.println(decrypt(orignial,8));
 }

 }