java RSA非对称加密

package Util;

import java.security.MessageDigest;

import javax.crypto.KeyGenerator;
import javax.crypto.Mac;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
 
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
 
public abstract class Coder {
    public static final String KEY_SHA = "SHA";
    public static final String KEY_MD5 = "MD5";
     
    /**
     * MAC算法可选以下多种算法
     * 
     * <pre>
     * HmacMD5 
     * HmacSHA1 
     * HmacSHA256 
     * HmacSHA384 
     * HmacSHA512
     * </pre>
     */ 
    public static final String KEY_MAC = "HmacMD5";
     
    /**
     * BASE64解密
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decryptBASE64( String key ) throws Exception{
        return (new BASE64Decoder()).decodeBuffer(key);
    }
     
    /**
     * BASE64加密
     * @param key
     * @return
     * @throws Exception
     */
    public static String encryptBASE64( byte[] key) throws Exception{
        return (new BASE64Encoder()).encodeBuffer(key);
    }
     
    /**
     * MD5 加密
     * @param data
     * @return
     * @throws Exception
     */
    public static byte[] encryptMD5( byte[] data) throws Exception {
        MessageDigest md5 = MessageDigest.getInstance(KEY_MD5);
        md5.update(data);
         
        return md5.digest();
    }
     
    /**
     * SHA 加密
     * @param data
     * @return
     * @throws Exception
     */
    public static byte[] encryptSHA( byte[] data) throws Exception {
        MessageDigest sha = MessageDigest.getInstance(KEY_SHA);
        sha.update(data);
         
        return sha.digest();
    }
     
    /**
     * 初始化HMAC密钥
     * 
     * @return
     * @throws Exception
     */ 
    public static String initMacKey() throws Exception{
        KeyGenerator keyGenerator = KeyGenerator.getInstance(KEY_MAC);
         
        SecretKey secretKey = keyGenerator.generateKey();
        return encryptBASE64(secretKey.getEncoded());
    }
     
    /**
     * HMAC  加密
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encryptHMAC( byte[] data, String key) throws Exception{
        SecretKey secretKey = new SecretKeySpec(decryptBASE64(key), KEY_MAC);
        Mac mac = Mac.getInstance(secretKey.getAlgorithm());
        mac.init(secretKey);
        return mac.doFinal(data);
    }
}

package Util;

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 java.util.HashMap;
import java.util.Map;
 
import javax.crypto.Cipher;
 
 
public abstract class RSACoder extends Coder{
    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";
     
    /**
     * 用私钥对信息生成数字签名
     * @param data 加密数据
     * @param privateKey 私钥
     * @return
     * @throws Exception
     */
    public static String sign(byte[] data, String privateKey) throws Exception {
        //解密由base64编码的私钥
        byte[] keyBytes = decryptBASE64(privateKey);
         
        PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(keyBytes);
         
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
         
        //取私钥对象
        PrivateKey pKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
         
        //用私钥生成数字签名
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initSign(pKey);
        signature.update(data);
         
        return encryptBASE64(signature.sign());
    }
     
    /**
     * 校验数字签名
     * @param data 加密数据
     * @param publicKey 公钥
     * @param sign 数字签名
     * @return
     * @throws Exception
     */
    public static boolean verify(byte[] data, String publicKey, String sign) throws Exception{
         
        //解密有base64编码的公钥
        byte[] keyBytes = decryptBASE64(publicKey);
         
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
         
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
         
        //取公钥对象
        PublicKey pKey = keyFactory.generatePublic(keySpec);
         
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initVerify(pKey);
        signature.update(data);
        //验证签名是否正常
        return signature.verify(decryptBASE64(sign));
    }
     
    /**
     * 解密
     *  用私钥解密
     * @param data 加密数据
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decryptPrivateKey(byte[] data, String key) throws Exception{
        byte[] keyBytes = decryptBASE64(key);
         
        //取得私钥
        PKCS8EncodedKeySpec encodedKeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory factory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key pKey = factory.generatePrivate(encodedKeySpec);
         
        //对数据解密
        Cipher cipher = Cipher.getInstance(factory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, pKey);
         
        return cipher.doFinal(data);
    }
     
    /**
     * 用公钥解密
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPublicKey( byte[] data, String key) throws Exception{
         
        //解密
        byte[] keyBytes = decryptBASE64(key);
         
        //取得公钥
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key pKey = keyFactory.generatePublic(keySpec);
         
        //对数据解密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, pKey);
         
        return cipher.doFinal(data);
    }
     
    /**
     * 用公钥加密
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPublicKey( byte[] data, String key) throws Exception{
         
        byte[] keyBytes = decryptBASE64(key);
         
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key pKey = keyFactory.generatePublic(keySpec);
         
         
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, pKey);
         
        return cipher.doFinal(data);
    }
     
    /**
     * 用私钥加密
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPrivateKey(byte[] data, String key) throws Exception{
         
        byte[] keyBytes = decryptBASE64(key);
         
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateKey = keyFactory.generatePrivate(keySpec);
         
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, privateKey);
         
        return cipher.doFinal(data);
    }
     
    /**
     * 取得私钥
     * @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());
    }
     
    /**
     * 取得公钥
     * @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());
    }
    /**
     * 初始化密钥
     * @return
     * @throws Exception
     */
    public static Map<String, Object> initKey() throws Exception{
         
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(KEY_ALGORITHM);
        keyPairGenerator.initialize(1024);
         
        KeyPair keyPair = keyPairGenerator.generateKeyPair();
        //公钥
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
         
        //私钥
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
         
        Map<String, Object> keyMap = new HashMap<String, Object>(2);
        keyMap.put(PRIVATE_KEY, privateKey);
        keyMap.put(PUBLIC_KEY, publicKey);
        return keyMap;
    }
}

测试：

package test;
import java.util.Map;
import Util.RSACoder;
/**
 * 测试类
 * @author m1539
 *
 */
public class test {
	private static String publicKey;
    private static String privateKey;
	
	public static void main(String[] args) {
		
/************************  获取 公钥，私钥  ****************************************************************/		
		
		try {
			Map<String, Object> keyMap = RSACoder.initKey();
			publicKey = RSACoder.getPublicKey(keyMap);
	        privateKey = RSACoder.getPrivateKey(keyMap);
		} catch (Exception e) {
			e.printStackTrace();
		}
         
        System.out.println("公钥：\n" + publicKey);
        System.out.println("私钥：\n" + privateKey);
        
/************************  客户端与服务端交互 *************************************/    
        
        try {
        	/*****  服务端--> 客户端   *****/
        	//第一步 数据源
        	String inputStr = "密钥加密";
            byte[] data = inputStr.getBytes();//每次的得到的字节数组是不一样的。
        	//第二步 私钥加密
			byte[] encodedData = RSACoder.encryptByPrivateKey(data, privateKey);
			//第三步 私钥进行数据签名
	        String sign = RSACoder.sign(encodedData, privateKey);
	        
	        
	        /*****  客户端解析  ******/
	        //第一步 公钥验证数字签名
	        boolean flag = RSACoder.verify(encodedData, publicKey, sign);
	        if(flag) {
	        	//第二步 用公钥对数据解密
		        byte[] decodedData = RSACoder.decryptByPublicKey(encodedData, publicKey);
		        System.out.println("加密前数据-：" + new String(data) + "  ,   解密后数据： " + new String(decodedData));
	        }
	        
	        
	        
	        /*****  客户端-->服务端 *******/
	        //使用公钥加密数据
	        byte[] encodedData1 = RSACoder.encryptByPublicKey("公钥加密".getBytes(), publicKey);
	        
	        /***** 服务端解析  ******/
	        //使用私钥解密数据
	        byte[] decodedData1 = RSACoder.decryptPrivateKey(encodedData1, privateKey);
	        
	        System.out.println("加密前数据：公钥加密  ,  解密后数据： " + new String(decodedData1));
		} catch (Exception e) {
			e.printStackTrace();
		}
        
	}

}