RSA加密算法的簡單案例

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 工具類。提供加密，解密，生成密鑰對等方法。
 * 需要到http://www.bouncycastle.org下載bcprov-jdk14-123.jar。
 * 
 */
public class RSAUtil {
/**
* * 生成密鑰對 *
* 
* @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;// 沒什么好說的了，這個值關系到塊加密的大小，可以更改，但是不要太大，否則效率會低
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);
// 生成密鑰
oos.writeObject(kp);
oos.close();
fos.close();
}
/**
* * 生成公鑰 *
* 
* @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());
}
}
/**
* * 生成私鑰 *
* 
* @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
* 加密的密鑰 *
* @param data
* 待加密的明文數(shù)據(jù) *
* @return 加密后的數(shù)據(jù) *
* @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();// 獲得加密塊大小，如：加密前數(shù)據(jù)為128個byte，而key_size=1024
// 加密塊大小為127
// byte,加密后為128個byte;因此共有2個加密塊，第一個127
// byte第二個為1個byte
int outputSize = cipher.getOutputSize(data.length);// 獲得加密塊加密后塊大小
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);
// 這里面doUpdate方法不可用，查看源代碼后發(fā)現(xiàn)每次doUpdate后并沒有什么實際動作除了把byte[]放到
// ByteArrayOutputStream中，而最后doFinal的時候才將所有的byte[]進行加密，可是到了此時加密塊大小很可能已經(jīng)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
* 解密的密鑰 *
* @param raw
* 已經(jīng)加密的數(shù)據(jù) *
* @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 {
 //對密碼進行翻轉如輸入ab翻轉后為ba
 StringBuffer sb = new StringBuffer(); 
 sb.append(new String(clinetPassword));
 String bb = sb.reverse().toString();
 //進行加密
 byte[] en_test = RSAUtil.encrypt(RSAUtil.getKeyPair().getPublic(),bb.getBytes()); 
 //進行解密，如果數(shù)據(jù)庫里面保存的是加密碼，則此處不需要進行解密
 byte[] de_test = RSAUtil.decrypt(RSAUtil.getKeyPair().getPrivate(),en_test); 
 //返回加密密碼
 clinetPassword=new String(de_test);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return clinetPassword; //即獲取加密密碼再與數(shù)據(jù)庫密碼匹配。 
 }
@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); //獲取輸入的用戶名 
 var password = FR.cjkEncode(document.getElementById("password").value); //獲取輸入的參數(shù) 
 $.ajax({ 
 url : "ReportServer?op=auth_login&fr_username=" + username + "&fr_password=" + password, //將用戶名和密碼發(fā)送到報表認證地址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(); //認證成功跳轉頁面，因為ajax不支持重定向所有需要跳轉的設置 
 } 
 else{ 
 alert("用戶名密碼錯誤！") //認證失敗 
 } 
 } 
 }) 
} 
</script>
</head>
<body>
<p>
請登錄
</p>
<form name="login" method="POST">
<p>
用戶名:
<input id="username" type="text" />
</p>
<p>
密 碼:
<input id="password" type="password" />
</p>
<input type="button" value="登錄" onclick="doSubmit()" />
</form>
</body>
</html>