【AES】

一種對稱加密演算法，DES的取代者。

【程式碼】

程式碼比較多，有一部分非本文章內容程式碼，具體自己看吧。

package com.uikoo9.util.encrypt;

import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.spec.SecretKeySpec;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import com.uikoo9.util.QStringUtil;

/**
 * 編碼工具類
 * 1.將byte[]轉為各種進位制的字串
 * 2.base 64 encode
 * 3.base 64 decode
 * 4.獲取byte[]的md5值
 * 5.獲取字串md5值
 * 6.結合base64實現md5加密
 * 7.AES加密
 * 8.AES加密為base 64 code
 * 9.AES解密
 * 10.將base 64 code AES解密
 * @author uikoo9
 * @version 0.0.7.20140601
 */
public class QEncodeUtil {
	
	public static void main(String[] args) throws Exception {
		String content = "我愛你";
		System.out.println("加密前：" + content);

		String key = "123456";
		System.out.println("加密金鑰和解密金鑰：" + key);
		
		String encrypt = aesEncrypt(content, key);
		System.out.println("加密後：" + encrypt);
		
		String decrypt = aesDecrypt(encrypt, key);
		System.out.println("解密後：" + decrypt);
	}
	
	/**
	 * 將byte[]轉為各種進位制的字串
	 * @param bytes byte[]
	 * @param radix 可以轉換進位制的範圍，從Character.MIN_RADIX到Character.MAX_RADIX，超出範圍後變為10進位制
	 * @return 轉換後的字串
	 */
	public static String binary(byte[] bytes, int radix){
		return new BigInteger(1, bytes).toString(radix);// 這裡的1代表正數
	}
	
	/**
	 * base 64 encode
	 * @param bytes 待編碼的byte[]
	 * @return 編碼後的base 64 code
	 */
	public static String base64Encode(byte[] bytes){
		return new BASE64Encoder().encode(bytes);
	}
	
	/**
	 * base 64 decode
	 * @param base64Code 待解碼的base 64 code
	 * @return 解碼後的byte[]
	 * @throws Exception
	 */
	public static byte[] base64Decode(String base64Code) throws Exception{
		return QStringUtil.isEmpty(base64Code) ? null : new BASE64Decoder().decodeBuffer(base64Code);
	}
	
	/**
	 * 獲取byte[]的md5值
	 * @param bytes byte[]
	 * @return md5
	 * @throws Exception
	 */
	public static byte[] md5(byte[] bytes) throws Exception {
		MessageDigest md = MessageDigest.getInstance("MD5");
		md.update(bytes);
		
		return md.digest();
	}
	
	/**
	 * 獲取字串md5值
	 * @param msg 
	 * @return md5
	 * @throws Exception
	 */
	public static byte[] md5(String msg) throws Exception {
		return QStringUtil.isEmpty(msg) ? null : md5(msg.getBytes());
	}
	
	/**
	 * 結合base64實現md5加密
	 * @param msg 待加密字串
	 * @return 獲取md5後轉為base64
	 * @throws Exception
	 */
	public static String md5Encrypt(String msg) throws Exception{
		return QStringUtil.isEmpty(msg) ? null : base64Encode(md5(msg));
	}
	
	/**
	 * AES加密
	 * @param content 待加密的內容
	 * @param encryptKey 加密金鑰
	 * @return 加密後的byte[]
	 * @throws Exception
	 */
	public static byte[] aesEncryptToBytes(String content, String encryptKey) throws Exception {
		KeyGenerator kgen = KeyGenerator.getInstance("AES");
		kgen.init(128, new SecureRandom(encryptKey.getBytes()));

		Cipher cipher = Cipher.getInstance("AES");
		cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(kgen.generateKey().getEncoded(), "AES"));
		
		return cipher.doFinal(content.getBytes("utf-8"));
	}
	
	/**
	 * AES加密為base 64 code
	 * @param content 待加密的內容
	 * @param encryptKey 加密金鑰
	 * @return 加密後的base 64 code
	 * @throws Exception
	 */
	public static String aesEncrypt(String content, String encryptKey) throws Exception {
		return base64Encode(aesEncryptToBytes(content, encryptKey));
	}
	
	/**
	 * AES解密
	 * @param encryptBytes 待解密的byte[]
	 * @param decryptKey 解密金鑰
	 * @return 解密後的String
	 * @throws Exception
	 */
	public static String aesDecryptByBytes(byte[] encryptBytes, String decryptKey) throws Exception {
		KeyGenerator kgen = KeyGenerator.getInstance("AES");
		kgen.init(128, new SecureRandom(decryptKey.getBytes()));
		
		Cipher cipher = Cipher.getInstance("AES");
		cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(kgen.generateKey().getEncoded(), "AES"));
		byte[] decryptBytes = cipher.doFinal(encryptBytes);
		
		return new String(decryptBytes);
	}
	
	/**
	 * 將base 64 code AES解密
	 * @param encryptStr 待解密的base 64 code
	 * @param decryptKey 解密金鑰
	 * @return 解密後的string
	 * @throws Exception
	 */
	public static String aesDecrypt(String encryptStr, String decryptKey) throws Exception {
		return QStringUtil.isEmpty(encryptStr) ? null : aesDecryptByBytes(base64Decode(encryptStr), decryptKey);
	}
	
}
 

加密前：我愛你
加密金鑰和解密金鑰：123456
加密後：A63fa7DjAe3yYji44BTm1g==
解密後：我愛你