RSA加/解密工具类-RSAUtil

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.crypto.Cipher;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.security.Key;

/**
 * Copyright (C), 2011-2018 {company}
 * FileName: 
 * Author: xxx
 * Email: xxx
 * Date: 2018/6/6 14:11
 * Description:
 * History:
 * <Author>      <Time>    <version>    <desc>
 * {xxx}   14:11    1.0          Create
 */
public class RSAUtil {
    private static final Logger log = LoggerFactory.getLogger(RSAUtil.class);
    /** 指定加密算法为RSA */
    private static final String ALGORITHM = "RSA";
    /** 指定公钥存放文件 */
    private static String PUBLIC_KEY_FILE = "merkey.public";
    /** 指定私钥存放文件 */
    private static String PRIVATE_KEY_FILE = "merkey.private";

    public static void main(String[] args) throws Exception {

        String source = "你好nihao";// 要加密的字符串
        System.out.println("准备用公钥加密的字符串为：" + source);

        String cryptograph = encrypt(source);// 生成的密文
        System.out.print("用公钥加密后的结果为:" + cryptograph);
        System.out.println();

        String target = decrypt(cryptograph);// 解密密文
        System.out.println("用私钥解密后的字符串为：" + target);
        System.out.println();
    }

    /**
     * 加密方法
     * @param source 源数据
     * @return
     * @throws Exception
     */
    public static String encrypt(String source) throws Exception {

        Key publicKey = getKey(PUBLIC_KEY_FILE);

        /** 得到Cipher对象来实现对源数据的RSA加密 */
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        byte[] b = source.getBytes();
        /** 执行加密操作 */
        byte[] b1 = cipher.doFinal(b);
        BASE64Encoder encoder = new BASE64Encoder();
        return encoder.encode(b1);
    }

    /**
     * 解密算法
     * @param cryptograph    密文
     * @return
     * @throws Exception
     */
    public static String decrypt(String cryptograph) throws Exception {

        Key privateKey = getKey(PRIVATE_KEY_FILE);

        /** 得到Cipher对象对已用公钥加密的数据进行RSA解密 */
        Cipher cipher = Cipher.getInstance(ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        BASE64Decoder decoder = new BASE64Decoder();
        byte[] b1 = decoder.decodeBuffer(cryptograph);

        /** 执行解密操作 */
        byte[] b = null;
        try {
            b = cipher.doFinal(b1);
            return new String(b);
        }catch (Exception e){
            log.error("解密失败，秘钥不正确", e);
        }
        return "";
    }

    private static Key getKey(String fileName) throws Exception, IOException {
        Key key;
        ObjectInputStream ois = null;
        try {
            /** 将文件中的私钥对象读出 */
            ois = new ObjectInputStream(new FileInputStream(fileName));
            key = (Key) ois.readObject();
        } catch (Exception e) {
            throw e;
        } finally {
            if(ois != null){
                ois.close();
            }
        }
        return key;
    }
}