JAVA实现RSA加密,非对称加密算法

java

浏览数:140

2019-1-8


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();
        }
    }

}