JAVA实现RSA加密,非对称加密算法

RSA.java

package org.icesnow.jeasywx.util.security;

import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
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;

import org.apache.log4j.Logger;

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

/**
 * @author: 782987839@qq.com
 * @date：2016-3-23下午12:25:07
 * @version: 1.0
 * @describe: JAVA实现RSA加密,非对称加密算法
 *
 */
public class RSA {
  private static Logger logger = Logger.getLogger(RSA.class);

	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";

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

		// 公钥
		RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
//		logger.info("------" + publicKey);
		// 私钥
		RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
//		logger.info("------" + publicKey);

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

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

	/**
	 * 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());
	}

	/**
	 * 解密<br>
	 * 用私钥解密
	 *
	 * @param data
	 * @param key
	 * @return
	 * @throws Exception
	 */
	public static byte[] decryptByPrivateKey(byte[] data, String key)
			throws Exception {
		// 对密钥解密
		byte[] keyBytes = decryptBASE64(key);

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

		// 对数据解密
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.DECRYPT_MODE, privateKey);

		return cipher.doFinal(data);
	}

	/**
	 * 解密<br>
	 * 用公钥解密
	 *
	 * @param data
	 * @param key
	 * @return
	 * @throws Exception
	 */
	public static byte[] decryptByPublicKey(byte[] data, String key)
			throws Exception {
		// 对密钥解密
		byte[] keyBytes = decryptBASE64(key);

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

		// 对数据解密
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.DECRYPT_MODE, publicKey);

		return cipher.doFinal(data);
	}

	/**
	 * 加密<br>
	 * 用公钥加密
	 *
	 * @param data
	 * @param key
	 * @return
	 * @throws Exception
	 */
	public static byte[] encryptByPublicKey(byte[] data, String key)
			throws Exception {
		// 对公钥解密
		byte[] keyBytes = decryptBASE64(key);

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

		// 对数据加密
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.ENCRYPT_MODE, publicKey);

		return cipher.doFinal(data);
	}

	/**
	 * 加密<br>
	 * 用私钥加密
	 *
	 * @param data
	 * @param key
	 * @return
	 * @throws Exception
	 */
	public static byte[] encryptByPrivateKey(byte[] data, String key)
			throws Exception {
		// 对密钥解密
		byte[] keyBytes = decryptBASE64(key);

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

		// 对数据加密
		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
		cipher.init(Cipher.ENCRYPT_MODE, privateKey);

		return cipher.doFinal(data);
	}

	/**
	 * 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);

		// 构造PKCS8EncodedKeySpec对象
		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);

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

		// 取私钥匙对象
		PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);

		// 用私钥对信息生成数字签名
		Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
		signature.initSign(priKey);
		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 校验成功返回true 失败返回false
	 * @throws Exception
	 *
	 */
	public static boolean verify(byte[] data, String publicKey, String sign)
			throws Exception {

		// 解密由base64编码的公钥
		byte[] keyBytes = decryptBASE64(publicKey);

		// 构造X509EncodedKeySpec对象
		X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);

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

		// 取公钥匙对象
		PublicKey pubKey = keyFactory.generatePublic(keySpec);

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

		// 验证签名是否正常
		return signature.verify(decryptBASE64(sign));
	}

	private static byte[] decryptBASE64(String key) throws Exception {
		return (new BASE64Decoder()).decodeBuffer(key);
	}

	private static String encryptBASE64(byte[] key) throws Exception {
		return (new BASE64Encoder()).encodeBuffer(key);
	}

	public static void main(String[] args) {
		Map<String, Object> keyMap;
		try {
			//取得公钥和么私钥
			keyMap = initKey();
			String publicKey = getPublicKey(keyMap);
			logger.info("字符类型公钥:" + publicKey);

			String privateKey = getPrivateKey(keyMap);
			logger.info("字符类型私钥:" + privateKey);

			System.err.println("公钥加密——私钥解密");
	        String source = "这是一行没有任何意义的文字，你看完了等于没看，不是吗？";
	        System.out.println("\r加密前文字：\r\n" + source);
	        byte[] data = source.getBytes();
	        byte[] encodedData = encryptByPublicKey(data, publicKey);
	        System.out.println("加密后文字：\r\n" + encryptBASE64(encodedData));
	        byte[] decodedData = decryptByPrivateKey(encodedData, privateKey);
	        String target = new String(decodedData);
	        System.out.println("解密后文字: \r\n" + target);

	        System.err.println("私钥加密——公钥解密");
	        String source1 = "这是一行测试RSA数字签名的无意义文字";
	        System.out.println("原文字：\r\n" + source1);
	        byte[] data1 = source1.getBytes();
	        byte[] encodedData1 = encryptByPrivateKey(data1, privateKey);
	        System.out.println("加密后：\r\n" + new String(encodedData1));
	        byte[] decodedData1 = decryptByPublicKey(encodedData1, publicKey);
	        String target1 = new String(decodedData1);
	        System.out.println("解密后: \r\n" + target1);
	        System.err.println("私钥签名——公钥验证签名");
	        String sign = sign(encodedData, privateKey);
	        System.err.println("签名:\r" + sign);
	        boolean status = verify(encodedData, publicKey, sign);
	        System.err.println("验证结果:\r" + status);
//			//对内容进行加密和解密
			String str = "this is test RSA";
			byte[] strByte = str.getBytes();
//			//私钥加密
			byte[] encode = encryptByPrivateKey(strByte,privateKey);
			logger.info("私钥加密结果:" + encryptBASE64(encode));
			//公钥解密
			byte[] decode = decryptByPublicKey(encode,publicKey);
			logger.info("公钥解密结果:" + new String(decode));

		} catch (Exception e) {
			e.printStackTrace();
		}
	}

}