DES algorithm

DES algorithm is well explained by J. Orlin Grabbe in his article.
Follow http://www.orlingrabbe.com/des.htm

DES implementation

Source code Language : Java
Crypto Packages are used

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/**
 * implement DES algorithm
 * @author chakreshprasad
 */

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.security.spec.KeySpec;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class des
{
Cipher ecipher;
Cipher dcipher;
KeySpec keysp;
SecretKeyFactory keyf;
byte keyasbyte[];
String enkey;
Cipher cipher;
SecretKey skey;
des() throws Exception
{
    enkey="hi.i.am.chakresh";
    keyasbyte=enkey.getBytes("UTF8");                 //utf8 is unicode format
    keysp=new DESKeySpec(keyasbyte);
    keyf=SecretKeyFactory.getInstance("DES");     //DES is encryption scheme
    cipher=Cipher.getInstance("DES");
    skey=keyf.generateSecret(keysp);
}

/*Encrypt a string*/

public String encrypt(String plain) throws Exception
{
    String enstring="";
    cipher.init(Cipher.ENCRYPT_MODE, skey);
    byte[] plaintext=plain.getBytes("UTF8");
    byte[] encrytext=cipher.doFinal(plaintext);
    BASE64Encoder base64en=new BASE64Encoder();
    enstring=base64en.encode(encrytext);
    return enstring;
}

/*Decrypt a string */

public String decrypt(String enstring)throws Exception
{
    String destring="";
    cipher.init(Cipher.DECRYPT_MODE, skey);
    BASE64Decoder base64de=new BASE64Decoder();
    byte[] enctext=base64de.decodeBuffer(enstring);
    byte plain[]=cipher.doFinal(enctext);
    destring=byte2string(plain);
    return destring;  
}
public String byte2string(byte plain[])
{
    StringBuffer str=new StringBuffer();
    for(int i=0;i<plain.length;i++)
        str.append((char)plain[i]);
    return str.toString();
}
    public static void main(String[] args) throws Exception
    {

       /*Generate an encrypter*/

       des ds=new des();
       BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
       String plain="",ciphertext="";
       System.out.println("Enter plain text : ");
       plain=br.readLine();
       ciphertext=ds.encrypt(plain);
       System.out.println("\nCipher text: "+ciphertext);
       plain=ds.decrypt(ciphertext);
       System.out.println("\nPlain text: "+plain);
      
    }

}

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Output:


Enter plain text :
chakreshprasad mahajan

Cipher text: qYv2ruDW4Fn8i+tTzdyCab5I3RvWxfw+

Plain text: chakreshprasad mahajan