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Java-web中利用RSA进行加密解密操作的方法示例

前言

最近在看，网络安全方面的问题，我们可以使用RSA进行非对称加密防止，获取用户信息。首先我们看下java下操作RSA进行加密解密算法，代码如下：

package com.jb.test;
 
import java.security.InvalidKeyException;
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 javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
 
import org.apache.commons.codec.binary.Hex;
 
public class RSAEntry {
 
 /**
 * @Title: main
 * @Description: RSA加密算法，解密算法
 * @param args
 * void
 * @throws NoSuchAlgorithmException 
 * @throws NoSuchPaddingException 
 * @throws InvalidKeyException 
 * @throws BadPaddingException 
 * @throws IllegalBlockSizeException 
 * 
 * @throws
 */
 public static void main(String[] args) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
// Security.getProviders();//获取所有支持的加密算法
 //采用非对称加密解密算法
 //生成密钥实例
 KeyPairGenerator keygen = KeyPairGenerator.getInstance("RSA");
 SecureRandom random = new SecureRandom();
 random.setSeed(System.currentTimeMillis());//设置随机种子
 keygen.initialize(512, random);//设置密钥长度，应为64的整数倍
 //生成密钥公钥对
 KeyPair keyPair = keygen.generateKeyPair();
 //获取公钥
 PublicKey pubkey = keyPair.getPublic();
 //获取私钥
 PrivateKey prikey = keyPair.getPrivate();
 //测试数据
 String data = "测试数据";
 //使用公钥进行加密
 //构建加密解密类
 Cipher cipher = Cipher.getInstance("RSA");
 cipher.init(Cipher.ENCRYPT_MODE, pubkey);//设置为加密模式
 byte[] jmdata = cipher.doFinal(data.getBytes());
 //打印加密后数据
 System.out.println(new String(Hex.encodeHex(jmdata)));
 //改为解密模式进行解密
 cipher.init(Cipher.DECRYPT_MODE, prikey);//会用私钥解密
 jmdata = cipher.doFinal(jmdata);
 System.out.println(new String(jmdata));
 
 }
}

在web应用中，我们可以通过js进行前端加密，java进行后台解密，已达到我们的目的。这里需要注意的是，要想实现正确的加密解密算法，需要使用bcprov-ext-jdk15on-147.jar。

首先创建系统的密钥提供者：

package com.jb.test;
 
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
 
import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.jcajce.provider.asymmetric.rsa.BCRSAPublicKey;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
 
/**
 * RSA初始化类
 * @author nmm
 * 结合前台的js使用的话，主要需要指定密钥提供者，即引入bcprov-ext-jdk15on-147.jar并使用其中的提供者
 */
public class RsaInitUtil {
 
 private static KeyPair keyPair;
 
 private static RsaInitUtil util;
 
 private RsaInitUtil(){
 try {
 if(keyPair == null) {
 //如果想要能够解密js的加密文件，使用此提供者是必须的
 KeyPairGenerator keygen = KeyPairGenerator.getInstance("RSA", new BouncyCastleProvider());
 SecureRandom random = new SecureRandom();
 random.setSeed(System.currentTimeMillis());
 keygen.initialize(512, random);//设置512位长度
 keyPair = keygen.generateKeyPair();
 }
 } catch (Exception e) {
 e.printStackTrace();
 }
 }
 
 public static RsaInitUtil getInstance(){
 synchronized ("rsa") {
 if(util == null) {
 util = new RsaInitUtil();
 }
 }
 return util;
 }
 
 /**
 * 
 * 功能说明：[获取公钥]
 * @return
 * 创建者:Nmm, Aug 19, 2013
 */
 public PublicKey getPublicKey(){
 return keyPair.getPublic();
 }
 
 public PrivateKey getPrivateKey(){
 return keyPair.getPrivate();
 }
 
 /**
 * 
 * 功能说明：[获取公钥字符串]
 * @return
 * 创建者:Nmm, Aug 19, 2013
 */
 public String getPublicKeyStr(){
 //根据我们的提供者，这里获取的是该类型公钥
 BCRSAPublicKey pk = (BCRSAPublicKey) getPublicKey();
 String str = new String(Hex.encodeHex(pk.getModulus().toByteArray()));
 System.out.println(str);
 //获取入口10001一般都为这个
 String ss = new String(Hex.encodeHex(pk.getPublicExponent().toByteArray()));
 //获取转换字符串
 System.out.println(b2Hex(pk.getModulus().toByteArray()));
 return ss + str;
 }
 /**
 * 
 * 功能说明：[手动转换]
 * @param byteArray
 * @return
 * 创建者:Nmm, Aug 19, 2013
 */
 private String b2Hex(byte[] byteArray) {
 StringBuilder sb = new StringBuilder();
 for(int i = 0; i < byteArray.length; i++ ) {
 int zhz = byteArray[i];
 if(zhz < 0) {
 zhz += 256;
 }
 if(zhz < 16) {
 sb.append("0");
 }
 sb.append(Integer.toHexString(zhz));
 }
 return sb.toString();
 }
}

前台引入RSA.js,BigInt.js和Barrett.js并采用如下方法加密：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@page import="com.jb.test.RsaInitUtil"%>
<%
 
 RsaInitUtil rsa = RsaInitUtil.getInstance();
 String my = rsa.getPublicKeyStr();
 String exp = my.substring(0,6);
 String mou = my.substring(6);
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
 <head>
 <title>RSA测试</title>
 <script type="text/javascript" src="RSA.js"></script>
 <script type="text/javascript" src="BigInt.js"></script>
 <script type="text/javascript" src="Barrett.js"></script>
 </head>
 
 <body>
 </body>
</html>
<script type="text/javascript">
 
 var m = '<%=mou%>';
 var e = '<%=exp%>';
 
 var key = '';
 setMaxDigits(128);
 alert(e);
 key = new RSAKeyPair(e,'',m);
 var res = encryptedString(key,encodeURIComponent('测试数据'));
 
 window.location.href = 'rsaDecTry.do?res=' + res;
 
</script>

后台解密算法为：

package com.jb.test;
 
import java.net.URLDecoder;
import java.security.NoSuchAlgorithmException;
 
import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
 
import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
 
/**
 * Rsa加密的控制层
 * @author nmm
 *
 */
@Controller("rsaController")
public class RsaController {
 
 private RsaInitUtil rsaUtil = RsaInitUtil.getInstance();
 
 /**
 * 
 * 功能说明：[解密方法]
 * @param res
 * 创建者:Nmm, Aug 19, 2013
 * @throws NoSuchPaddingException 
 * @throws NoSuchAlgorithmException 
 */
 @RequestMapping("rsaDecTry.do")
 public void decodeTry(String res) throws Exception {
 Cipher cipher = Cipher.getInstance("RSA",new BouncyCastleProvider());//必须指定此提供者
 cipher.init(Cipher.DECRYPT_MODE, rsaUtil.getPrivateKey());
 System.out.println(res);
 byte[] buff = cipher.doFinal(Hex.decodeHex(res.toCharArray()));
 //将字符串转为字符
 StringBuilder sb = new StringBuilder(new String(buff,"UTF-8"));
 //解密后的内容是倒叙的
 sb.reverse();
 //进行URL解密，主要是为了中文乱码问题
 String result = URLDecoder.decode(sb.toString(), "UTF-8");
 System.out.println(result);
 
 }
}

至此可完成，整个加密解密过程，下面大家可以把rsa相关的内容全部整合到一个工具类中，不用想这里处理。

下面为RSA加密解密工具类：

package com.jb.framework.filter;
 
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.math.BigInteger;
import java.net.URLDecoder;
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.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;
import java.util.Calendar;
 
import javax.crypto.Cipher;
 
import org.apache.commons.codec.binary.Hex;
import org.bouncycastle.jcajce.provider.asymmetric.rsa.BCRSAPublicKey;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
 
/**
 * 
 * @Package: com.jb.framework.filter<br>
 * @ClassName: RSAUtil<br>
 * @Description: RSA加密工具类，这里我们是每次系统启动时声称一套公钥，私钥，因此不能将加密串存入数据库中，如果要这么做可以预先生成密钥队写入到文件中<br>
 */
public class RSAUtil {
 
 private RSAUtil(){}
 
 public static final String keyPubFile = "rsaPubKey.bin";
 public static final String keyPriFile = "rsaPriKey.bin";
 
 private static RSAUtil rsa;
 //密钥生成器
 private PublicKey publicKey;
 //密钥队
 private PrivateKey privateKey; 
 
 
 public static RSAUtil getInstance(){
 synchronized ("rsa") {
 if(rsa == null) {
 rsa = new RSAUtil();
 rsa.init();
 }
 }
 return rsa;
 }
 /**
 * 
 * @Title: init
 * @Description: 初始化方法
 * void
 * @throws
 */
 private void init() {
 //构建RSA算法
 try {
 KeyPairGenerator kengen = KeyPairGenerator.getInstance("RSA",new BouncyCastleProvider());
 //构建随机种子
 SecureRandom random = new SecureRandom();
 random.setSeed(Calendar.getInstance().getTimeInMillis());
 kengen.initialize(512, random);//采用512位加密
 KeyPair keyPair = kengen.generateKeyPair();
 publicKey = keyPair.getPublic();
 privateKey = keyPair.getPrivate();
 } catch (NoSuchAlgorithmException e) {
 e.printStackTrace();
 }
 }
 /**
 * 
 * @Title: getPublicKey
 * @Description: 获取公钥
 * @return
 * PublicKey
 * @throws
 */
 public PublicKey getPublicKey(){
 return this.publicKey;
 }
 /**
 * 
 * @Title: getPrivateKey
 * @Description: 获取私钥
 * @return
 * PrivateKey
 * @throws
 */
 public PrivateKey getPrivateKey(){
 return this.privateKey;
 }
 /**
 * 
 * @Title: getPublicKeyStr
 * @Description: 获取系统公钥字符串，前6位为exponentk,后面为modlus
 * @return
 * String
 * @throws
 */
 public String getPublicKeyStr(){
 BCRSAPublicKey pk = (BCRSAPublicKey) getPublicKey();
 String pubStr = "";
 pubStr += b2hex(pk.getPublicExponent().toByteArray());
 pubStr += b2hex(pk.getModulus().toByteArray());
 return pubStr;
 }
 /**
 * 
 * @Title: entryText
 * @Description: 使用默认公钥进行加密
 * @param text
 * @return
 * String
 * @throws
 */
 public String encryText(String text) {
 return encryText(text,getPublicKey());
 }
 /**
 * 
 * @Title: entryText
 * @Description: 使用指定公钥进行加密，解决长字符串加密
 * @param text
 * @param publicKey2
 * @return
 * String
 * @throws
 */
 public String encryText(String text, PublicKey pk) {
 try {
 Cipher cipher = Cipher.getInstance("RSA",new BouncyCastleProvider());
 cipher.init(Cipher.ENCRYPT_MODE, pk);
 int block = cipher.getBlockSize();//获取最大加密块
 int j = 0;
 StringBuilder sb = new StringBuilder();
 byte[] targetData = text.getBytes("UTF-8");
 while (targetData.length - j*block > 0) {
 byte[] jmdata = cipher.doFinal(targetData,j*block,Math.min(targetData.length - j*block, block));
 sb.append(b2hex(jmdata));
 j++;
 }
 return sb.toString();
 } catch (Exception e) {
 e.printStackTrace();
 }
 return null;
 }
 /**
 * 
 * @Title: decryText
 * @Description: 使用默认的私钥进行解密解密算法
 * @param text
 * @return
 * String
 * @throws
 */
 public String decryText(String text) {
 return decryText(text,getPrivateKey());
 }
 /**
 * 
 * @Title: decryText
 * @Description: 指定私钥进行解密，增加对于大字符串的解密操作
 * @param text
 * @param privateKey2
 * @return
 * String
 * @throws
 */
 public String decryText(String text, PrivateKey pk) {
 try {
 Cipher cipher = Cipher.getInstance("RSA", new BouncyCastleProvider());
 cipher.init(Cipher.DECRYPT_MODE, pk);
 byte[] targetBuff = Hex.decodeHex(text.replace(" ", "").toCharArray());
 int block = cipher.getBlockSize();
 int j = 0;
 StringBuilder sb = new StringBuilder();
 while (targetBuff.length - j * block > 0) {
 byte[] jmdata = cipher.doFinal(targetBuff,j*block,block);
 sb.append(new String(jmdata,"UTF-8"));
 j++;
 }
 return sb.toString();
 
 } catch (Exception e) {
 e.printStackTrace();
 }
 return null;
 }
 /**
 * 
 * @Title: decryTextByUrl
 * @Description: 解密前台传递的加密串，为防止中文乱码，前台字符串最好使用encodeURIComponent方法进行url编码
 * @param text
 * @return
 * String
 * @throws
 */
 public String decryTextByUrl(String text) {
 try {
 Cipher cipher = Cipher.getInstance("RSA", new BouncyCastleProvider());
 cipher.init(Cipher.DECRYPT_MODE, getPrivateKey());
 byte[] targetBuff = Hex.decodeHex(text.replace(" ", "").toCharArray());
 int block = cipher.getBlockSize();
 int j = 0;
 StringBuilder sb = new StringBuilder();
 while (targetBuff.length - j * block > 0) {//处理大字符串的加密解密处理
 byte[] jmdata = cipher.doFinal(targetBuff,j*block,block);
 sb.append(new StringBuilder(new String(jmdata,"UTF-8")).reverse());
 j++;
 }
 String res = URLDecoder.decode(sb.toString(), "UTF-8");
 return res;
 
 } catch (Exception e) {
 e.printStackTrace();
 }
 return null;
 }
 /**
 * 
 * @Title: createPubKey
 * @Description: 根据指定的幂和模式生成公钥
 * @param exponent
 * @param modules
 * @return
 * PublicKey
 * @throws
 */
 public PublicKey createPubKey(byte[] exponent,byte[]modules) {
 try {
 KeyFactory keyFactory = KeyFactory.getInstance("RSA", new BouncyCastleProvider());
 RSAPublicKeySpec rsaKs = new RSAPublicKeySpec(new BigInteger(modules),new BigInteger(exponent));
 return keyFactory.generatePublic(rsaKs);
 
 } catch (Exception e) {
 e.printStackTrace();
 }
 
 return null;
 }
 /**
 * 
 * @Title: createPubKey
 * @Description: 根据指定的幂和模式生成公钥
 * @param exponent
 * @param modules
 * @return
 * PublicKey
 * @throws
 */
 public PrivateKey createPriKey(byte[] exponent,byte[]modules) {
 try {
 KeyFactory keyFactory = KeyFactory.getInstance("RSA", new BouncyCastleProvider());
 RSAPrivateKeySpec rsaKs = new RSAPrivateKeySpec(new BigInteger(modules),new BigInteger(exponent));
 return keyFactory.generatePrivate(rsaKs);
 
 } catch (Exception e) {
 e.printStackTrace();
 }
 return null;
 }
 /**
 * 
 * @Title: saveKeyToFile
 * @Description: 保存公钥和私钥到文件中
 * void
 * @throws
 */
 public void saveKeyToFile() {
 PublicKey pk = getPublicKey();
 PrivateKey prik = getPrivateKey();
 
 String path = RSAUtil.class.getClassLoader().getResource("").getPath();
 ObjectOutputStream outPub = null;
 ObjectOutputStream outPri = null;
 try {
 System.out.println(path + keyPubFile);
 outPub = new ObjectOutputStream(new FileOutputStream(path + keyPubFile));
 outPri = new ObjectOutputStream(new FileOutputStream(path + keyPriFile));
 outPub.writeObject(pk);
 outPri.writeObject(prik);
 } catch (Exception e) {
 e.printStackTrace();
 }finally {
 try {
 outPub.close();
 outPri.close();
 } catch (IOException e) {
 e.printStackTrace();
 }
 
 }
 }
 /**
 * 
 * @Title: readKey
 * @Description: 读取密钥
 * @param isPub
 * @return
 * Object
 * @throws
 */
 public Object readKey(boolean isPub) {
 String path = RSAUtil.class.getClassLoader().getResource("").getPath();
 ObjectInputStream in = null;
 try {
 if(isPub) {
 path += keyPubFile;
 in = new ObjectInputStream(new FileInputStream(path));
 PublicKey pk = (PublicKey) in.readObject();
 return pk;
 }else {
 path += keyPriFile;
 in = new ObjectInputStream(new FileInputStream(path));
 PrivateKey pk = (PrivateKey) in.readObject();
 return pk;
 }
 } catch (Exception e) {
 e.printStackTrace();
 }finally {
 try {
 in.close();
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
 return null;
 }
 
 
 /**
 * 
 * @Title: b2hex
 * @Description: 将二进制转为16进制字符串
 * @param buff
 * @return
 * String
 * @throws
 */
 public String b2hex(byte[] buff) {
 StringBuilder sb = new StringBuilder();
 for(int i = 0; i < buff.length; i++) {
 int z = buff[i];
 if(z < 0) {
 z+= 256;
 }
 if(z < 16) {
 sb.append("0");
 }
 sb.append(Integer.toHexString(z));
 }
 return sb.toString();
 }
}

下载：http://xiazai.jb51.net/201808/yuanma/rsajar_jb51.rar

总结

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