自动生成RSA密钥，并进行加密和解密2

package com.digican.books.a0102.b0101;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.math.BigInteger;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;

/**
 * 2010年9月1日
 * @author 姚大庆
 */
public class DigicanRSA {
	
	public static void main(String[] args) throws Exception {
		//生成密钥
		//getAutoCreateRSA("d:\\key\\rsapublickey","d:\\key\\rsaprivatekey");
		//用公钥对AES密钥加密
		/*byte[] b = getRSAPublicEncode("d:\\key\\rsapublickey","d:\\key\\aeskey");
		FileOutputStream fos = new FileOutputStream("d:\\key\\rsajiamiaes");
		fos.write(b);
		fos.flush();
		fos.close();*/
		//用私钥来解AES密钥
		byte[] b = getRSAPrivateDecode("d:\\key\\rsaprivatekey","d:\\key\\rsajiamiaes");
		FileOutputStream fos = new FileOutputStream("d:\\key\\rsajiemiaes");
		fos.write(b);
		fos.flush();
		fos.close();
	}

	/**
	 * 生成密钥
	 * 自动产生RSA1024位密钥；并保持到文件里
	 * rsaPublicKeyFilePath 公钥的文件路径名，例如：d:\publickey.txt
	 * rsaPrivateKeyFilePath 公钥的文件路径名，例如：d:\privatekey.txt
	 * @throws NoSuchAlgorithmException 
	 * @throws IOException 
	 */
	public static void getAutoCreateRSA(String rsaPublicKeyFilePath,String rsaPrivateKeyFilePath) throws NoSuchAlgorithmException, IOException{
		KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
		kpg.initialize(1024);
		KeyPair kp = kpg.genKeyPair();
		PublicKey puk = kp.getPublic();
		PrivateKey prk = kp.getPrivate();
		FileOutputStream pufos = new FileOutputStream(rsaPublicKeyFilePath);
		ObjectOutputStream puoos = new ObjectOutputStream(pufos);
		puoos.writeObject(puk);
		puoos.flush();
		puoos.close();
		FileOutputStream prfos = new FileOutputStream(rsaPrivateKeyFilePath);
		ObjectOutputStream proos = new ObjectOutputStream(prfos);
		proos.writeObject(prk);
		proos.flush();
		proos.close();
	}
	
	/**
	 * 加密
	 * 使用非对称方式生成的公钥进行加密RSA1024
	 * 使用公钥把AES密钥进行加密
	 * rsaPublicKeyFilePath 公钥文件路径；例如：d:\\rsapublickey.txt
	 * aesKeyFilePath 对称密钥文件路径
	 * @throws IOException 
	 * @throws ClassNotFoundException 
	 */
	public static byte[] getRSAPublicEncode(String rsaPublicKeyFilePath,String aesKeyFilePath) throws IOException, ClassNotFoundException {
		//读取公钥
		FileInputStream fis = new FileInputStream(rsaPublicKeyFilePath);
		ObjectInputStream ois = new ObjectInputStream(fis);
		RSAPublicKey pbk = (RSAPublicKey)ois.readObject();
		BigInteger e = pbk.getPublicExponent();
		BigInteger n = pbk.getModulus();
		
		//读取对称密钥
		File file = new File(aesKeyFilePath);
		byte[] baes = new byte[(int) file.length()];
		FileInputStream fisaes = new FileInputStream(file);
		fisaes.read(baes);
		
		BigInteger m = new BigInteger(baes);
		BigInteger c = m.modPow(e, n);//因为RSA算法要求整型数m的值必须小于n，所以需要计算
		byte[] bb = c.toByteArray();
		return bb;
	}
	
	/**
	 * 解密
	 * 通过非对称生成的公钥和私钥
	 * 用私钥解公钥加密数据RSA1024
	 * rsaPrivateKeyFilePath 私钥文件路径；例如：d:\\rsaprivatekey.txt
	 * publicEncodeFilePath 公钥加密后的数据；例如：d:\\rsapublickeyjiamihou.txt
	 */
	public static byte[] getRSAPrivateDecode(String rsaPrivateKeyFilePath,String publicEncodeFilePath) throws Exception{
		/*BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(publicEncodeFilePath)));//加密后文件
		String ctext = br.readLine();
		BigInteger c = new BigInteger(ctext);*/
		
		File file = new File(publicEncodeFilePath);
		byte[] bjia = new byte[(int) file.length()];
		FileInputStream fisaes = new FileInputStream(file);
		fisaes.read(bjia);
		BigInteger c = new BigInteger(bjia);
				
		FileInputStream fis = new FileInputStream(rsaPrivateKeyFilePath);
		ObjectInputStream ois = new ObjectInputStream(fis);
		RSAPrivateKey prk = (RSAPrivateKey)ois.readObject();
		BigInteger d = prk.getPrivateExponent();
		BigInteger n = prk.getModulus();
		BigInteger m = c.modPow(d, n);
		byte[] mt = m.toByteArray();
		return mt;
	}
}