JCA Cipher加解密

JCA加密/解密的介紹:
使用Cipher進行
1.加/解密資料
2.使用Blowfish與OFB mode
3.人工產生IV(Initialization Vector)

import java.security.SecureRandom;

import javax.crypto.KeyGenerator;

import javax.crypto.SecretKey;

import javax.crypto.Cipher;

import java.security.NoSuchAlgorithmException;

import java.security.InvalidKeyException;

import java.security.InvalidAlgorithmParameterException;

import javax.crypto.NoSuchPaddingException;

import javax.crypto.IllegalBlockSizeException;

import javax.crypto.BadPaddingException;

import javax.crypto.spec.IvParameterSpec;

import org.apache.commons.codec.binary.Base64;



/**

 * 

 * @author Frank Kim 

 */

public class CipherWithIvExample {



    public static void main(String args[]) {

        try {

            KeyGenerator kg = KeyGenerator.getInstance("Blowfish");

            SecretKey sk = kg.generateKey();

            

            byte[] origData = "data".getBytes();

        

            Cipher cipher = Cipher.getInstance("Blowfish/OFB/PKCS5Padding");

            

            byte[] randomBytes = new byte[8];

          SecureRandom random = SecureRandom.getInstance("SHA1PRNG");

          random.nextBytes(randomBytes);

          IvParameterSpec ivSp1 = new IvParameterSpec(randomBytes);

            

            cipher.init(Cipher.ENCRYPT_MODE, sk, ivSp1);

            byte[] encryText = cipher.doFinal(origData);

            

            byte[] iv = cipher.getIV();

            IvParameterSpec ivSp2 = new IvParameterSpec(iv);

            

            cipher.init(Cipher.DECRYPT_MODE, sk, ivSp2);

            byte[] decryText = cipher.doFinal(encryText);

            

            String origString = new String(origData);

            String decryString = new String(decryText);

            System.out.println("Data matches? " + origString.equals(decryString));

            

  } catch (NoSuchAlgorithmException e1) {

         System.err.println(e1);

  } catch (InvalidKeyException e2) {

      System.err.println(e2);

  } catch (NoSuchPaddingException e3) {

      System.err.println(e3);

  }catch (IllegalBlockSizeException e4) {

      System.err.println(e4);

  } catch (BadPaddingException e5) {

      System.err.println(e5);

  } catch (InvalidAlgorithmParameterException e6) {

      System.err.println(e6);

  }

    }

 

}