JAVA实现RSA加密,非对称加密算法

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mob604756f6b718 2019-01-04 13:37:00
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();
    }
  }

}