RSA加密算法的简单案例

package com.fr.privilege;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.math.BigInteger;
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.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;
import javax.crypto.Cipher;
/**
 * 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 {
/**
* * 生成密钥对 *
* 
* @return KeyPair *
* @throws EncryptException
*/
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();
saveKeyPair(keyPair);
return keyPair;
} catch (Exception e) {
throw new Exception(e.getMessage());
}
}
public static KeyPair getKeyPair() throws Exception {
FileInputStream fis = new FileInputStream("C:/RSAKey.txt");
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("C:/RSAKey.txt");
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 key
*  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 key
*  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();
String test = "hello world";
byte[] en_test = encrypt(getKeyPair().getPublic(), test.getBytes());
System.out.println("123:" + new String(en_test));
byte[] de_test = decrypt(getKeyPair().getPrivate(), en_test);
System.out.println(new String(de_test));
}
}
 

package com.fr.privilege; 
import com.fr.privilege.providers.dao.AbstractPasswordValidator; 
public class TestPasswordValidatorRSA extends AbstractPasswordValidator{ 
 //@Override
 public String encodePassword( String clinetPassword) {
 try {
 //对密码进行翻转如输入ab翻转后为ba
 StringBuffer sb = new StringBuffer(); 
 sb.append(new String(clinetPassword));
 String bb = sb.reverse().toString();
 //进行加密
 byte[] en_test = RSAUtil.encrypt(RSAUtil.getKeyPair().getPublic(),bb.getBytes()); 
 //进行解密，如果数据库里面保存的是加密码，则此处不需要进行解密
 byte[] de_test = RSAUtil.decrypt(RSAUtil.getKeyPair().getPrivate(),en_test); 
 //返回加密密码
 clinetPassword=new String(de_test);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return clinetPassword; //即获取加密密码再与数据库密码匹配。 
 }
@Override
public boolean validatePassword(String arg0, String arg1) {
// TODO Auto-generated method stub
return false;
}
}

<%@page contentType="text/html" pageEncoding="UTF-8"%>
<%@page import="com.fr.privilege.providers.dao.RSAUtil"%>
<%!public String Testmo() {
String module = "";
try {
java.security.interfaces.RSAPublicKey rsap = (java.security.interfaces.RSAPublicKey) RSAUtil
.getKeyPair().getPublic();
module = rsap.getModulus().toString(16);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return module;
}%>
<%!public String Testem() {
String empoent = "";
try {
java.security.interfaces.RSAPublicKey rsap = (java.security.interfaces.RSAPublicKey) RSAUtil
.getKeyPair().getPublic();
empoent = rsap.getPublicExponent().toString(16);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return empoent;
}%>
<html>
<head>
<script type="text/javascript"
src="ReportServer?op=emb&resource=finereport.js"></script>
<script type="text/javascript" src="js/RSA.js"></script>
<script type="text/javascript" src="js/BigInt.js"></script>
<script type="text/javascript" src="js/Barrett.js"></script>
<script type="text/javascript"> 
function bodyRSA() 
{ 
 setMaxDigits(130); 
 var a = "<%=Testmo()%>";
var b = "<%=Testem()%>";
key = new RSAKeyPair(b,"",a);
} 
function doSubmit() { 
bodyRSA(); 
 var username = FR.cjkEncode(document.getElementById("username").value); //获取输入的用户名 
 var password = FR.cjkEncode(document.getElementById("password").value); //获取输入的参数 
 $.ajax({ 
 url : "ReportServer?op=auth_login&fr_username=" + username + "&fr_password=" + password, //将用户名和密码发送到报表认证地址op=auth_login 
 data : {__redirect__ : 'false'}, 
 complete : function(res) { 
  var jo = FR.jsonDecode(res.responseText); 
  if(jo.url) { 
  window.location=jo.url+ "&_=" + new Date().getTime(); //认证成功跳转页面，因为ajax不支持重定向所有需要跳转的设置 
  } 
  else{ 
  alert("用户名密码错误！") //认证失败 
  } 
 } 
 }) 
} 
</script>
</head>
<body>
<p>
请登录
</p>
<form name="login" method="POST">
<p>
用户名:
<input id="username" type="text" />
</p>
<p>
密 码:
<input id="password" type="password" />
</p>
<input type="button" value="登录" onclick="doSubmit()" />
</form>
</body>
</html>