[JAVA_Security]Java(자바) 데이터 암호화 XOR

@ 데이터 암호화를 위해 논리 연산의 XOR를 상용한 소스이다.

 public class XorSample  
 {  
   public final static byte[] KEY = "4d2dg".getBytes( );  
   public static void main( String[] args )  
   {  
     XorSample sample = new XorSample( );  
     sample.exec( );  
   }  
   public void exec( )  
   {  
     StringBuffer data = new StringBuffer( );  
     for ( int i = 0 ; i < 30 ; i++ )  
     {  
       data.append( i );  
       data.append( "안녕하세요!" );  
       data.append( i );  
     }  
     byte[] encrypt = xor( data.toString( ).getBytes( ) , KEY );  
     System.out.println( encrypt.length );  
     System.out.println( "변환:" + new String( encrypt ) );  
     byte[] decrypt = xor( encrypt , KEY );  
     System.out.println( "재변환:" + new String( decrypt ) );  
     System.out.println( decrypt.length );  
   }  
   public byte[] xor( byte[] data , byte[] key )  
   {  
     final int orgLength = data.length;  
     final int keyLength = key.length;  
     final byte[] converted = new byte[orgLength];  
     for ( int i = 0 , j = 0 ; i < orgLength ; i++ , j++ )  
     {  
       converted[ i ] = ( byte ) ( data[ i ] ^ key[ j ] );  
       if ( j >= ( keyLength - 1 ) )  
       {  
         j = 0;  
       }  
     }  
     return converted;  
   }  
 }  

[Java Design Pattern_5]Singleton 샘플 코드1

Triple.java


package com.sgdata.singleton;

public class Triple {
private static Triple[] triple = new Triple[ ] {
new Triple(0) ,
new Triple(1) ,
new Triple(2) ,
};
private int id;
private Triple(int id){
System.out.println("The instance " + id + " is created. ");
this.id = id;
}
public static Triple getInstance(int id){
return triple[id];
}
public String toString(){
return "[Triple id=" + id + "]";
}
}

Main.java

package com.sgdata.singleton;

public class Main {

public static void main(String[] args) {

System.out.println("Start");

for(int i=0;i<9;i++){

Triple triple = Triple.getInstance(i%3);

System.out.println(i+":"+triple);

}

System.out.println("End.");

}

}

[Java Design Pattern_4]Factory Method 샘플 코드2

1. Framework

- Product  클래스 : '제품'을 표현한 추상 클래스로서 추상 메서드 use만 선언 되어 있다.


package com.sgdata.factorymethod;
 
public abstract class Product {
     public abstract void use();
}


- Factory 클래스 : 템플릿 패턴이 적용되어 있습니다. 추상 메서드                                                    createProduct,registerProduct는 하위 클래스에서 구현 합니다. 


package com.sgdata.factorymethod;

public abstract class Factory {
    public final Product create(String owner) {
         Product p = createProduct(owner);
         registerProduct(p);
         return p;
    }
    protected abstract Product createProduct(String owner);
    protected abstract void registerProduct(Product product);
}



2. Idcard

- IDCard 클래스 : Product 클래스를 상속받아서 구현.


package com.sgdata.factorymethod;

public class IDCard extends Product{

private String owner;
private int serial;

IDCard(String owner, int serial){
System.out.println(owner +"("+serial+")"+"의 카드를 만듭니다.");
this.owner = owner;
this.serial = serial;
}

@Override
public void use() {
// TODO Auto-generated method stub
System.out.println(owner + "(" + serial +")" +"의 카드를 사용합니다.");
}
public String getOwner(){
return owner;
}
public int getSerial(){
return serial;
}
}

- IDCardFactory : Factory 클래스를 상속받아서 구현.

package com.sgdata.factorymethod;

import java.util.HashMap;

import java.util.Hashtable;

public class IDCardFactory extends Factory{

private HashMap database = new HashMap();

private int serial = 100;

@Override

protected synchronized Product createProduct(String owner) {

// TODO Auto-generated method stub

return new IDCard(owner, serial++);

}

@Override

protected void registerProduct(Product product) {

// TODO Auto-generated method stub

IDCard card = (IDCard)product;

database.put(new Integer(card.getSerial()), card.getOwner());

}

public HashMap getDatabase(){

return database;

}

}

3. Main

package com.sgdata.factorymethod;

public class Main {  

     public static void main(String[] args) {  

          Factory factory = new IDCardFactory();  

          Product card1 = factory.create("홍길동");  

          Product card2 = factory.create("김민수");  

          Product card3 = factory.create("구로이드");  

          card1.use();  

          card2.use();  

          card3.use();  

     }  

}