文件加密解密算法(Java源码)
java,file,算法,加密解密,java源码
package com.crypto.encrypt;
import java.security.SecureRandom;
import java.io.*;
import javax.crypto.spec.DESKeySpec;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.Cipher;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.BadPaddingException;
import javax.crypto.IllegalBlockSizeException;
import java.lang.reflect.Constructor;
import java.security.spec.KeySpec;
import java.lang.reflect.InvocationTargetException;
public class EncryptData {
private String keyfile=null;
public EncryptData() {
}
public EncryptData(String keyfile) {
this.keyfile=keyfile;
}
/**
* 加密文件
* @param filename String 源路径
* @param filenamekey String 加密后的路径
*/
public void createEncryptData(String filename,String filenamekey) throws
IllegalStateException, IllegalBlockSizeException, BadPaddingException,
NoSuchPaddingException, InvalidKeySpecException, NoSuchAlgorithmException,
InvalidKeyException, IOException, InstantiationException,
IllegalAccessException, IllegalArgumentException,
InvocationTargetException, NoSuchMethodException, SecurityException,
ClassNotFoundException, IllegalStateException, IllegalBlockSizeException,
BadPaddingException, NoSuchPaddingException, InvalidKeySpecException,
NoSuchAlgorithmException, InvalidKeyException, IOException {
//验证keyfile
if(keyfile==null || keyfile.equals(""))
{
throw new NullPointerException("无效的key文件路径");
}
encryptData(filename,filenamekey);
}
/**
* 加密类文件
* @param filename String 原始的类文件
* @param encryptfile String 加密后的类文件
* @throws IOException
* @throws InvalidKeyException
* @throws NoSuchAlgorithmException
* @throws InvalidKeySpecException
* @throws NoSuchPaddingException
* @throws NoSuchAlgorithmException
* @throws BadPaddingException
* @throws IllegalBlockSizeException
* @throws IllegalStateException
*/
private void encryptData(String filename,String encryptfile) throws IOException, InvalidKeyException,
NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException,
NoSuchAlgorithmException, BadPaddingException, IllegalBlockSizeException,
IllegalStateException, ClassNotFoundException, SecurityException,
NoSuchMethodException, InvocationTargetException,
IllegalArgumentException, IllegalAccessException, InstantiationException {
byte data[]=Util.readFile(filename);
// 执行加密操作
byte encryptedClassData[] = getencryptData(data);
// 保存加密后的文件,覆盖原有的类文件。
Util.writeFile(encryptedClassData,encryptfile);
}
/**
* 直接获得加密数据
* @param bytes byte[]
* @throws IllegalStateException
* @throws IllegalBlockSizeException
* @throws BadPaddingException
* @throws InvalidKeyException
* @throws NoSuchPaddingException
* @throws InvalidKeySpecException
* @throws NoSuchAlgorithmException
* @throws InstantiationException
* @throws IllegalAccessException
* @throws IllegalArgumentException
* @throws InvocationTargetException
* @throws NoSuchMethodException
* @throws SecurityException
* @throws ClassNotFoundException
* @throws IOException
* @return byte[]
*/
public byte[] createEncryptData(byte[] bytes) throws IllegalStateException,
IllegalBlockSizeException, BadPaddingException, InvalidKeyException,
NoSuchPaddingException, InvalidKeySpecException, NoSuchAlgorithmException,
InstantiationException, IllegalAccessException, IllegalArgumentException,
InvocationTargetException, NoSuchMethodException, SecurityException,
ClassNotFoundException, IOException {
bytes=getencryptData(bytes);
return bytes;
}
private byte[] getencryptData(byte[] bytes) throws IOException,
ClassNotFoundException, SecurityException, NoSuchMethodException,
InvocationTargetException, IllegalArgumentException,
IllegalAccessException, InstantiationException, NoSuchAlgorithmException,
InvalidKeySpecException, NoSuchPaddingException, NoSuchAlgorithmException,
InvalidKeyException, BadPaddingException, IllegalBlockSizeException,
IllegalStateException {
// 产生一个可信任的随机数源
SecureRandom sr = new SecureRandom();
//从密钥文件key Filename中得到密钥数据
byte[] rawKeyData = Util.readFile(keyfile);
// 从原始密钥数据创建DESKeySpec对象
Class classkeyspec=Class.forName(Util.getValue("keyspec"));
Constructor constructor = classkeyspec.getConstructor(new Class[]{byte[].class});
KeySpec dks = (KeySpec) constructor.newInstance(new Object[]{rawKeyData});
// 创建一个密钥工厂,然后用它把DESKeySpec转换成SecretKey对象
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(Util.getAlgorithm());
SecretKey key = keyFactory.generateSecret(dks);
// Cipher对象实际完成加密操作
Cipher cipher = Cipher.getInstance(Util.getAlgorithm());
// 用密钥初始化Cipher对象
cipher.init(Cipher.ENCRYPT_MODE, key, sr);
// 执行加密操作
bytes = cipher.doFinal(bytes);
// 返回字节数组
return bytes;
}
/**
* 设置key文件路径
* @param keyfile String
*/
public void setKeyFile(String keyfile)
{
this.keyfile=keyfile;
}
}
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