RSA加密例子和中途遇到的問題

在進行RSA加密例子

package test;
import java.io.IOException;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import sun.misc.BASE64Decoder; 
import sun.misc.BASE64Encoder;

import java.util.HashMap;
import java.util.Map;

import javax.crypto.Cipher;

public abstract class RSACoder {
	public static final String KEY_ALGORITHM = "RSA";
	public static final String SIGNATURE_ALGORITHM = "MD5withRSA";

	private static final String PUBLIC_KEY = "RSAPublicKey";
	private static final String PRIVATE_KEY = "RSAPrivateKey";


	public static byte[] decryptBASE64(String privateKey){
		byte[] output = null;
		try {
			output = (new BASE64Decoder()).decodeBuffer(privateKey);
			return  output;
		} catch (IOException e) {
			e.printStackTrace();
		}
		return output;  
	}


	public static String encryptBASE64( byte[] keyBytes){
         String s = (new BASE64Encoder()).encode(keyBytes);
         return s;
	}

	/**
	 * 用私鑰對信息生成數字簽名
	 * 
	 * @param data
	 *            加密數據
	 * @param privateKey
	 *            私鑰
	 * 
	 * @return
	 * @throws Exception
	 */
	public static String sign(byte[] data, String privateKey) throws Exception {
		// 解密由base64編碼的私鑰
		byte[] keyBytes = decryptBASE64(privateKey);

		// 構造PKCS8EncodedKeySpec對象
		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);

		// KEY_ALGORITHM 指定的加密算法
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);

		// 取私鑰匙對象
		PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);

		// 用私鑰對信息生成數字簽名
		Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
		signature.initSign(priKey);
		signature.update(data);

		return encryptBASE64(signature.sign());
	}

	/**
	 * 校驗數字簽名
	 * 
	 * @param data
	 *            加密數據
	 * @param publicKey
	 *            公鑰
	 * @param sign
	 *            數字簽名
	 * 
	 * @return 校驗成功返回true 失敗返回false
	 * @throws Exception
	 * 
	 */
	public static boolean verify(byte[] data, String publicKey, String sign)
			throws Exception {

		// 解密由base64編碼的公鑰
		byte[] keyBytes = decryptBASE64(publicKey);

		// 構造X509EncodedKeySpec對象
		X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);

		// KEY_ALGORITHM 指定的加密算法
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);

		// 取公鑰匙對象
		PublicKey pubKey = keyFactory.generatePublic(keySpec);

		Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
		signature.initVerify(pubKey);
		signature.update(data);

		// 驗證簽名是否正常
		return signature.verify(decryptBASE64(sign));
	}

	/**
	 * 解密<br>
	 * 用私鑰解密
	 * 
	 * @param data
	 * @param key
	 * @return
	 * @throws Exception
	 */
	public static byte[] decryptByPrivateKey(byte[] data, String key)
			throws Exception {
		// 對密鑰解密
		byte[] keyBytes = decryptBASE64(key);

		// 取得私鑰
		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
		Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);

		// 對數據解密
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.DECRYPT_MODE, privateKey);

		return cipher.doFinal(data);
	}

	/**
	 * 解密<br>
	 * 用公鑰解密
	 * 
	 * @param data
	 * @param key
	 * @return
	 * @throws Exception
	 */
	public static byte[] decryptByPublicKey(byte[] data, String key)
			throws Exception {
		// 對密鑰解密
		byte[] keyBytes = decryptBASE64(key);

		// 取得公鑰
		X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
		Key publicKey = keyFactory.generatePublic(x509KeySpec);

		// 對數據解密
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.DECRYPT_MODE, publicKey);

		return cipher.doFinal(data);
	}

	/**
	 * 加密<br>
	 * 用公鑰加密
	 * 
	 * @param data
	 * @param key
	 * @return
	 * @throws Exception
	 */
	public static byte[] encryptByPublicKey(byte[] data, String key)
			throws Exception {
		// 對公鑰解密
		byte[] keyBytes = decryptBASE64(key);

		// 取得公鑰
		X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
		Key publicKey = keyFactory.generatePublic(x509KeySpec);

		// 對數據加密
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.ENCRYPT_MODE, publicKey);

		return cipher.doFinal(data);
	}

	/**
	 * 加密<br>
	 * 用私鑰加密
	 * 
	 * @param data
	 * @param key
	 * @return
	 * @throws Exception
	 */
	public static byte[] encryptByPrivateKey(byte[] data, String key)
			throws Exception {
		// 對密鑰解密
		byte[] keyBytes = decryptBASE64(key);

		// 取得私鑰
		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
		Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);

		// 對數據加密
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.ENCRYPT_MODE, privateKey);

		return cipher.doFinal(data);
	}

	/**
	 * 取得私鑰
	 * 
	 * @param keyMap
	 * @return
	 * @throws Exception
	 */
	public static String getPrivateKey(Map<String, Object> keyMap)
			throws Exception {
		Key key = (Key) keyMap.get(PRIVATE_KEY);

		return encryptBASE64(key.getEncoded());
	}

	/**
	 * 取得公鑰
	 * 
	 * @param keyMap
	 * @return
	 * @throws Exception
	 */
	public static String getPublicKey(Map<String, Object> keyMap)
			throws Exception {
		Key key = (Key) keyMap.get(PUBLIC_KEY);

		return encryptBASE64(key.getEncoded());
	}

	/**
	 * 初始化密鑰
	 * 
	 * @return
	 * @throws Exception
	 */
	public static Map<String, Object> initKey() throws Exception {
		KeyPairGenerator keyPairGen = KeyPairGenerator
				.getInstance(KEY_ALGORITHM);
		keyPairGen.initialize(1024);

		KeyPair keyPair = keyPairGen.generateKeyPair();

		// 公鑰
		RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();

		// 私鑰
		RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();

		Map<String, Object> keyMap = new HashMap<String, Object>(2);

		keyMap.put(PUBLIC_KEY, publicKey);
		keyMap.put(PRIVATE_KEY, privateKey);
		return keyMap;
	}
}

測試類

package test;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import sun.misc.BASE64Decoder; 
import sun.misc.BASE64Encoder;
public class RSACoderTest {

package com;
import java.util.Map;
import sun.misc.BASE64Encoder;
public class RSACoderTest {
		static String privateKey ;
		static String publicKey ;
		public static void getKey() throws Exception {
		Map<String, Object> keyMap = RSACoder.initKey();

		publicKey = RSACoder.getPublicKey(keyMap);
		privateKey = RSACoder.getPrivateKey(keyMap);
		//公鑰生成
		System.out.println("public : "+publicKey);
		//私鑰生成
		System.out.println("private : "+privateKey);
	}
	public static void main(String[] args) throws Exception {
		 getKey() ;
//		System.err.println("公鑰加密——私鑰解密");
                //將明文轉換爲字節數組
		byte[] data = "serricee1".getBytes();
               //用公鑰加密
		byte[] encodedData = RSACoder.encryptByPublicKey(data, publicKey);
                //打印加密字符串 爲什麼使用BASE64Encoder 因爲在RSACoder里加密用的是 BASE64Encoder 加密
		String s = (new BASE64Encoder()).encode(encodedData);  
		System.err.println("加密: " +s);
//                //用私鑰解密
		byte[] decodedData = RSACoder.decryptByPrivateKey(RSACoder.decryptBASE64(s),privateKey);
//
//		
		System.out.println( "解密後: " + new String(decodedData));
	}


}

遇到的問題在
解密的時候 用new BASE64Encoder()).encode(keyBytes); 獲得明文發現明文長度只能是4的倍數而且不支持特殊字符串和中文不然解密出來不是多出來 就是解密不對 後面解密
直接用.getBytes() 和new String(decodedData)不用Base64的就好了