RSA使用前台公钥加密后台私钥解密实例

第一步:(百度搜索RSA获得公钥与私钥)--->拿到公钥就OK了--先备着等下要用到

第二步:工具类(这个写好的直接导入)---》里面有一个main方法可以先测试一下

/**
 * RSA 工具类。提供加密,解密,生成密钥对等方法。
 * 

* 需要到http://www.bouncycastle.org下载bcprov-jdk14-123.jar。 */ public class RSAUtil { private static String RSAKeyStore = "E:/RSAKey.txt"; /** * * 生成密钥对 * * * @return KeyPair * * @throws Exception */ public static KeyPair generateKeyPair() throws Exception { try { KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider()); final int KEY_SIZE = 1024;// 没什么好说的了,这个值关系到块加密的大小,可以更改,但是不要太大,否则效率会低 keyPairGen.initialize(KEY_SIZE, new SecureRandom()); KeyPair keyPair = keyPairGen.generateKeyPair(); System.out.println(keyPair.getPrivate()); System.out.println(keyPair.getPublic()); saveKeyPair(keyPair); return keyPair; } catch (Exception e) { throw new Exception(e.getMessage()); } } public static KeyPair getKeyPair() throws Exception { FileInputStream fis = new FileInputStream(RSAKeyStore); ObjectInputStream oos = new ObjectInputStream(fis); KeyPair kp = (KeyPair) oos.readObject(); oos.close(); fis.close(); return kp; } public static void saveKeyPair(KeyPair kp) throws Exception { FileOutputStream fos = new FileOutputStream(RSAKeyStore); ObjectOutputStream oos = new ObjectOutputStream(fos); // 生成密钥 oos.writeObject(kp); oos.close(); fos.close(); } /** * * 生成公钥 * * * @param modulus * * @param publicExponent * * @return RSAPublicKey * * @throws Exception */ public static RSAPublicKey generateRSAPublicKey(byte[] modulus, byte[] publicExponent) throws Exception { KeyFactory keyFac = null; try { keyFac = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider()); } catch (NoSuchAlgorithmException ex) { throw new Exception(ex.getMessage()); } RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(new BigInteger( modulus), new BigInteger(publicExponent)); try { return (RSAPublicKey) keyFac.generatePublic(pubKeySpec); } catch (InvalidKeySpecException ex) { throw new Exception(ex.getMessage()); } } /** * * 生成私钥 * * * @param modulus * * @param privateExponent * * @return RSAPrivateKey * * @throws Exception */ public static RSAPrivateKey generateRSAPrivateKey(byte[] modulus, byte[] privateExponent) throws Exception { KeyFactory keyFac = null; try { keyFac = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider()); } catch (NoSuchAlgorithmException ex) { throw new Exception(ex.getMessage()); } RSAPrivateKeySpec priKeySpec = new RSAPrivateKeySpec(new BigInteger( modulus), new BigInteger(privateExponent)); try { return (RSAPrivateKey) keyFac.generatePrivate(priKeySpec); } catch (InvalidKeySpecException ex) { throw new Exception(ex.getMessage()); } } /** * * 加密 * * * @param pk data 加密的密钥 * * @param data 待加密的明文数据 * * @return 加密后的数据 * * @throws Exception */ public static byte[] encrypt(PublicKey pk, byte[] data) throws Exception { try { Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider()); cipher.init(Cipher.ENCRYPT_MODE, pk); int blockSize = cipher.getBlockSize();// 获得加密块大小,如:加密前数据为128个byte,而key_size=1024 // 加密块大小为127 // byte,加密后为128个byte;因此共有2个加密块,第一个127 // byte第二个为1个byte int outputSize = cipher.getOutputSize(data.length);// 获得加密块加密后块大小 int leavedSize = data.length % blockSize; int blocksSize = leavedSize != 0 ? data.length / blockSize + 1 : data.length / blockSize; byte[] raw = new byte[outputSize * blocksSize]; int i = 0; while (data.length - i * blockSize > 0) { if (data.length - i * blockSize > blockSize) cipher.doFinal(data, i * blockSize, blockSize, raw, i * outputSize); else cipher.doFinal(data, i * blockSize, data.length - i * blockSize, raw, i * outputSize); // 这里面doUpdate方法不可用,查看源代码后发现每次doUpdate后并没有什么实际动作除了把byte[]放到 // ByteArrayOutputStream中,而最后doFinal的时候才将所有的byte[]进行加密,可是到了此时加密块大小很可能已经超出了 // OutputSize所以只好用dofinal方法。 i++; } return raw; } catch (Exception e) { throw new Exception(e.getMessage()); } } /** * * 解密 * * * @param pk 解密的密钥 * * @param raw 已经加密的数据 * * @return 解密后的明文 * * @throws Exception */ public static byte[] decrypt(PrivateKey pk, byte[] raw) throws Exception { try { Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider()); cipher.init(cipher.DECRYPT_MODE, pk); int blockSize = cipher.getBlockSize(); ByteArrayOutputStream bout = new ByteArrayOutputStream(64); int j = 0; while (raw.length - j * blockSize > 0) { bout.write(cipher.doFinal(raw, j * blockSize, blockSize)); j++; } /** * RSA 工具类。提供加密,解密,生成密钥对等方法。 *

* 需要到http://www.bouncycastle.org下载bcprov-jdk14-123.jar。 */ public class RSAUtil { private static String RSAKeyStore = "E:/RSAKey.txt"; /** * * 生成密钥对 * * * @return KeyPair * * @throws Exception */ public static KeyPair generateKeyPair() throws Exception { try { KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider()); final int KEY_SIZE = 1024;// 没什么好说的了,这个值关系到块加密的大小,可以更改,但是不要太大,否则效率会低 keyPairGen.initialize(KEY_SIZE, new SecureRandom()); KeyPair keyPair = keyPairGen.generateKeyPair(); System.out.println(keyPair.getPrivate()); System.out.println(keyPair.getPublic()); saveKeyPair(keyPair); return keyPair; } catch (Exception e) { throw new Exception(e.getMessage()); } } public static KeyPair getKeyPair() throws Exception { FileInputStream fis = new FileInputStream(RSAKeyStore); ObjectInputStream oos = new ObjectInputStream(fis); KeyPair kp = (KeyPair) oos.readObject(); oos.close(); fis.close(); return kp; } public static void saveKeyPair(KeyPair kp) throws Exception { FileOutputStream fos = new FileOutputStream(RSAKeyStore); ObjectOutputStream oos = new ObjectOutputStream(fos); // 生成密钥 oos.writeObject(kp); oos.close(); fos.close(); } /** * * 生成公钥 * * * @param modulus * * @param publicExponent * * @return RSAPublicKey * * @throws Exception */ public static RSAPublicKey generateRSAPublicKey(byte[] modulus, byte[] publicExponent) throws Exception { KeyFactory keyFac = null; try { keyFac = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider()); } catch (NoSuchAlgorithmException ex) { throw new Exception(ex.getMessage()); } RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(new BigInteger( modulus), new BigInteger(publicExponent)); try { return (RSAPublicKey) keyFac.generatePublic(pubKeySpec); } catch (InvalidKeySpecException ex) { throw new Exception(ex.getMessage()); } } /** * * 生成私钥 * * * @param modulus * * @param privateExponent * * @return RSAPrivateKey * * @throws Exception */ public static RSAPrivateKey generateRSAPrivateKey(byte[] modulus, byte[] privateExponent) throws Exception { KeyFactory keyFac = null; try { keyFac = KeyFactory.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider()); } catch (NoSuchAlgorithmException ex) { throw new Exception(ex.getMessage()); } RSAPrivateKeySpec priKeySpec = new RSAPrivateKeySpec(new BigInteger( modulus), new BigInteger(privateExponent)); try { return (RSAPrivateKey) keyFac.generatePrivate(priKeySpec); } catch (InvalidKeySpecException ex) { throw new Exception(ex.getMessage()); } } /** * * 加密 * * * @param pk data 加密的密钥 * * @param data 待加密的明文数据 * * @return 加密后的数据 * * @throws Exception */ public static byte[] encrypt(PublicKey pk, byte[] data) throws Exception { try { Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider()); cipher.init(Cipher.ENCRYPT_MODE, pk); int blockSize = cipher.getBlockSize();// 获得加密块大小,如:加密前数据为128个byte,而key_size=1024 // 加密块大小为127 // byte,加密后为128个byte;因此共有2个加密块,第一个127 // byte第二个为1个byte int outputSize = cipher.getOutputSize(data.length);// 获得加密块加密后块大小 int leavedSize = data.length % blockSize; int blocksSize = leavedSize != 0 ? data.length / blockSize + 1 : data.length / blockSize; byte[] raw = new byte[outputSize * blocksSize]; int i = 0; while (data.length - i * blockSize > 0) { if (data.length - i * blockSize > blockSize) cipher.doFinal(data, i * blockSize, blockSize, raw, i * outputSize); else cipher.doFinal(data, i * blockSize, data.length - i * blockSize, raw, i * outputSize); // 这里面doUpdate方法不可用,查看源代码后发现每次doUpdate后并没有什么实际动作除了把byte[]放到 // ByteArrayOutputStream中,而最后doFinal的时候才将所有的byte[]进行加密,可是到了此时加密块大小很可能已经超出了 // OutputSize所以只好用dofinal方法。 i++; } return raw; } catch (Exception e) { throw new Exception(e.getMessage()); } } /** * * 解密 * * * @param pk 解密的密钥 * * @param raw 已经加密的数据 * * @return 解密后的明文 * * @throws Exception */ public static byte[] decrypt(PrivateKey pk, byte[] raw) throws Exception { try { Cipher cipher = Cipher.getInstance("RSA", new org.bouncycastle.jce.provider.BouncyCastleProvider()); cipher.init(cipher.DECRYPT_MODE, pk); int blockSize = cipher.getBlockSize(); ByteArrayOutputStream bout = new ByteArrayOutputStream(64); int j = 0; while (raw.length - j * blockSize > 0) { bout.write(cipher.doFinal(raw, j * blockSize, blockSize)); j++; } return bout.toByteArray(); } catch (Exception e) { throw new Exception(e.getMessage()); } } /** * * * * * @param args * * @throws Exception */ public static void main(String[] args) throws Exception { RSAPublicKey rsap = (RSAPublicKey) RSAUtil.generateKeyPair().getPublic(); System.out.println("公钥"+rsap); String test = "hello world"; byte[] en_test = encrypt(getKeyPair().getPublic(), test.getBytes()); byte[] de_test = decrypt(getKeyPair().getPrivate(), en_test); System.out.println(new String(de_test)); } } return bout.toByteArray(); } catch (Exception e) { throw new Exception(e.getMessage()); } } /** * * * * * @param args * * @throws Exception */ public static void main(String[] args) throws Exception { RSAPublicKey rsap = (RSAPublicKey) RSAUtil.generateKeyPair().getPublic(); System.out.println("公钥"+rsap); String test = "hello world"; byte[] en_test = encrypt(getKeyPair().getPublic(), test.getBytes()); byte[] de_test = decrypt(getKeyPair().getPrivate(), en_test); System.out.println(new String(de_test)); } }

第三步:(前台页面如下)

需要导三个外部js插件如图

<%@ taglib prefix="form" uri="http://www.springframework.org/tags/form" %>
<%@ page language="java" pageEncoding="UTF-8" contentType="text/html; charset=UTF-8"%>


  
    登陆
    
    
    
    
    
  
  
  
<%--发送验证码--%>
uname:
Password:
验证码:

第四步:后台代码展示

   //登陆
    @RequestMapping("/Res")
    public  String LoginVerify(String result, Integer CodeValue, HttpServletRequest request) throws Exception {
        StringBuffer code = (StringBuffer) request.getSession().getAttribute("code");
        String s1 = code.toString();
        int i = Integer.parseInt(s1);
        String pwd;
        if (CodeValue==i){
            //将密码---》后端查询 此处不列举
            System.out.println("最先提交上来的密文为"+result);
            byte[] en_result = new BigInteger(result, 16).toByteArray();
            byte[] de_result = RSAUtil.decrypt(RSAUtil.getKeyPair().getPrivate(),en_result);
            String s = new String(de_result);
            System.out.println("还原密文"+s);
            //新键StringBuffer缓冲区
            StringBuffer sb = new StringBuffer();
            //在新建的字符串后  追加密文
            sb.append(s);
            pwd=sb.reverse().toString();
            System.out.println("=======================");
            pwd= URLDecoder.decode(pwd,"UTF-8");
            //将密码存储在request域中
            request.setAttribute("pwd",pwd);
            return  "/Success.jsp";
        }else {
            return "/Message.jsp";
        }
    }

第五步:前台页面显示直接从request域中取值就OK了

。。。。 

 

 

 

 

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