Encrypting a String with DES - Java Security

Java examples for Security:DES

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Description

Encrypting a String with DES

Demo Code


import java.io.UnsupportedEncodingException;

import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;

public class Main {
  public static void main(String[] args) {
    try {//from w  ww  . j a v a 2 s.co  m
      SecretKey key = KeyGenerator.getInstance("DES").generateKey();

      // Create encrypter/decrypter class
      DesEncrypter encrypter = new DesEncrypter(key);

      // Encrypt
      String encrypted = encrypter.encrypt("Don't tell anybody!");

      // Decrypt
      String decrypted = encrypter.decrypt(encrypted);
    } catch (Exception e) {
    }
  }
}

class DesEncrypter {
  Cipher ecipher;
  Cipher dcipher;

  DesEncrypter(SecretKey key) {
    try {
      ecipher = Cipher.getInstance("DES");
      dcipher = Cipher.getInstance("DES");
      ecipher.init(Cipher.ENCRYPT_MODE, key);
      dcipher.init(Cipher.DECRYPT_MODE, key);

    } catch (javax.crypto.NoSuchPaddingException e) {
    } catch (java.security.NoSuchAlgorithmException e) {
    } catch (java.security.InvalidKeyException e) {
    }
  }

  public String encrypt(String str) {
    try {
      // Encode the string into bytes using utf-8
      byte[] utf8 = str.getBytes("UTF8");

      // Encrypt
      byte[] enc = ecipher.doFinal(utf8);

      // Encode bytes to base64 to get a string
      return new sun.misc.BASE64Encoder().encode(enc);
    } catch (javax.crypto.BadPaddingException e) {
    } catch (IllegalBlockSizeException e) {
    } catch (UnsupportedEncodingException e) {
    } catch (java.io.IOException e) {
    }
    return null;
  }

  public String decrypt(String str) {
    try {
      // Decode base64 to get bytes
      byte[] dec = new sun.misc.BASE64Decoder().decodeBuffer(str);

      // Decrypt
      byte[] utf8 = dcipher.doFinal(dec);

      // Decode using utf-8
      return new String(utf8, "UTF8");
    } catch (javax.crypto.BadPaddingException e) {
    } catch (IllegalBlockSizeException e) {
    } catch (UnsupportedEncodingException e) {
    } catch (java.io.IOException e) {
    }
    return null;
  }
}

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