Java安全之秘密密钥

标签：秘密密钥   secretkey   对称加密   des   aes   

   在Java中，秘密密钥的抽象接口为javax.crypto.SecretKey，其算法类型为对称加密算法，对称加密算法的主要特点就是加密与解密用的是同一把密钥，对称加密算法主要有：DES,DESede,AES,Blowfish,RC2,RC4等。下面看一个使用例子：

package com.xtayfjpk.security;


import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.security.spec.KeySpec;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

import org.junit.Test;

public class SecretKeyTest {
	//对称加密算法，Java默认支持的算法有：AES、ARCFOUR、Blowfish、DES、DESede、HmacMD5、
	//HmacSHA1 HmacSHA256 HmacSHA384 HmacSHA512、RC2
	private static final String ALGORITHM = "DES";
	
	@Test
	public void testEncrypt() throws Exception {
		//获取加/解密器
		Cipher cipher = Cipher.getInstance(ALGORITHM);
		//生成秘密密钥
		SecretKey key = KeyGenerator.getInstance(ALGORITHM).generateKey();
		//将秘密写入文件中
		writeSecretKey("xtayfjpk.key", key, false);
		//加密时，必须初始化为加密模式
		cipher.init(Cipher.ENCRYPT_MODE, key);
		
		String myInfo = "我的明文";
		//加密
		byte[] results = cipher.doFinal(myInfo.getBytes());
		writeFile("content.dat", results);
	}
	
	
	
	@Test
	public void testDecrypt() throws Exception {
		//读取秘密密钥
		SecretKey key = readSecretKey("xtayfjpk.key", false);
		//读取加密后的数据
		byte[] contents = readFile("content.dat");
		Cipher cipher = Cipher.getInstance(ALGORITHM);
		//解密时，必须初始化为解密模式
		cipher.init(Cipher.DECRYPT_MODE, key);
		//解密，得到明文
		byte[] origins = cipher.doFinal(contents);
		System.out.println(new String(origins));
	}
	
	/** 读取文件内容至字节数组中 **/
	public byte[] readFile(String path) throws Exception {
		FileInputStream cntInput = new FileInputStream(path);
		ByteArrayOutputStream baos = new ByteArrayOutputStream();
		int b = -1;
		while((b=cntInput.read())!=-1) {
			baos.write(b);
		}
		cntInput.close();
		byte[] contents = baos.toByteArray();
		baos.close();
		return contents;
	}
	
	/** 将二进制数据写入文件 **/
	public void writeFile(String path, byte[] content) throws Exception {
		FileOutputStream fos = new FileOutputStream(path);
		fos.write(content);
		fos.close();
	}
	
	public SecretKey readSecretKey(String path, boolean encoded) throws Exception {
		if(encoded) {
			byte[] keyData = readFile(path);
			KeySpec keySpec = new DESKeySpec(keyData);
			//当读取秘密密钥编码数据时须使用此方式生成秘密密钥
			//Java文档中虽然明确说明SecretKeyFactory.getInstance支持AES算法，但事实上却不支持(JDK7)
			SecretKey key = SecretKeyFactory.getInstance(ALGORITHM).generateSecret(keySpec);
			return key;
		} else {
			FileInputStream fis = new FileInputStream(path);
			ObjectInputStream bis = new ObjectInputStream(fis);
			Object object = bis.readObject();
			bis.close();
			return (SecretKey) object;
		}
	}
	
	/** 秘密密钥写入文件有两种方式，一是利用Java对象的序列化机制，二是获取其编码数据(字节数据)写入文件 **/
	public void writeSecretKey(String path, SecretKey secretKey, boolean encoded) throws Exception {
		FileOutputStream fos = new FileOutputStream(path);
		if(encoded) {
			fos.write(secretKey.getEncoded());
			fos.close();
		} else {
			ObjectOutputStream oos = new ObjectOutputStream(fos);
			oos.writeObject(secretKey);
			oos.close();
		}
	}
}

Java安全之秘密密钥

标签：秘密密钥   secretkey   对称加密   des   aes   

原文地址：http://blog.csdn.net/xtayfjpk/article/details/46007887