java公钥加密_私钥解密_Java非对称加密(公钥加密，私钥解密)

import java.io.ByteArrayOutputStream;

import java.io.File;

import java.io.FileInputStream;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.security.Key;

import java.security.KeyPair;

import java.security.KeyPairGenerator;

import javax.crypto.Cipher;

/**

* 公钥加密，私钥解密(非对称加密)

*

*/

public class AsymmetricEncryption {

public static void main(String[] args) throws Exception {

publicEnrypy();

privateEncode();

}

/**

* 加密的方法,使用公钥进行加密

* @throws Exception

*/

public static void publicEnrypy() throws Exception {

Cipher cipher = Cipher.getInstance("RSA");

KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");

// 生成钥匙对

KeyPair keyPair = keyPairGenerator.generateKeyPair();

// 得到公钥

Key publicKey = keyPair.getPublic();

// 得到私钥

Key privateKey = keyPair.getPrivate();

// 设置为加密模式

cipher.init(Cipher.ENCRYPT_MODE, publicKey);

// 对数据进行加密

byte[] result = cipher.doFinal("aaa".getBytes());

//把私钥保存到硬盘上

saveKey(privateKey);

//把加密后的数据保存到硬盘上

saveData(result);

}

/**

* 解密的方法，使用私钥进行解密

* @throws Exception

*/

public static void privateEncode() throws Exception {

Cipher cipher = Cipher.getInstance("RSA");

// 从硬盘中读取私钥

Key privateKey = loadKey();

//设置为解密模式，用私钥解密

cipher.init(Cipher.DECRYPT_MODE, privateKey);

// 从硬盘中读取加密后的数据

byte[] data = loadData();

//对加密后的数据进行解密，返回解密后的结果

byte[] result = cipher.doFinal(data);

System.out.println(new String(result));

}

/**

* 从硬盘中加载加密后的文件

* @return

* @throws FileNotFoundException

* @throws IOException

*/

private static byte[] loadData() throws FileNotFoundException, IOException {

FileInputStream fileInputStream = new FileInputStream(new File(

"E://data.data"));

ByteArrayOutputStream outputStream = new ByteArrayOutputStream();

byte[] buffer = new byte[1024];

int len = 0;

while ((len = fileInputStream.read(buffer)) != -1) {

outputStream.write(buffer, 0, len);

}

fileInputStream.close();

return outputStream.toByteArray();

}

/**

* 从硬盘中加载私钥

* @return

* @throws IOException

* @throws FileNotFoundException

* @throws ClassNotFoundException

*/

private static Key loadKey() throws IOException, FileNotFoundException,

ClassNotFoundException {

ObjectInputStream inputStream = new ObjectInputStream(

new FileInputStream(new File("E://private_key")));

Key privateKey = (Key) inputStream.readObject();

return privateKey;

}

/**

* 把加密后的密文保存到硬盘上

* @param result

* @throws FileNotFoundException

* @throws IOException

*/

private static void saveData(byte[] result) throws FileNotFoundException,

IOException {

FileOutputStream fileOutputStream = new FileOutputStream(new File(

"E://data.data"));

fileOutputStream.write(result);

}

/**

* 把私钥保存到硬盘上

* @param privateKey

* @throws IOException

* @throws FileNotFoundException

*/

private static void saveKey(Key privateKey) throws IOException,

FileNotFoundException {

ObjectOutputStream outputStream = new ObjectOutputStream(

new FileOutputStream(new File("E://private_key")));

outputStream.writeObject(privateKey);

}

}