用Java编写的密码算法类

　　package data;

import Java.security.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.io.*;

/**
* Security 提供了一个安全算法类,其中包括对称密码算法和散列算法
*/
public final class Security
{
/**
* 对称加密方法
* @param byteSource 需要加密的数据
* @return 经过加密的数据
* @throws Exception
*/
public static byte[] symmetricEncrypto(byte[] byteSource) throws Exception
{
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try
{
int mode = Cipher.ENCRYPT_MODE;
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
byte[] keyData = {1, 9, 8, 2, 0, 8, 2, 1};
DESKeySpec keySpec = new DESKeySpec(keyData);
Key key = keyFactory.generateSecret(keySpec);
Cipher cipher = Cipher.getInstance("DES");
cipher.init(mode, key);
int blockSize = cipher.getBlockSize();
int position = 0;
int length = byteSource.length;
boolean more = true;
while(more)
{
if(position + blockSize <= length)
{
baos.write(cipher.update(byteSource, position, blockSize));
position += blockSize;
}
else
{
more = false;
}
}
if(position < length)
{
baos.write(cipher.doFinal(byteSource, position, length - position));
}
else
{
baos.write(cipher.doFinal());
}
return baos.toByteArray();
}
catch(Exception e)
{
throw e;
}
finally
{
baos.close();
}
}
/**
* 对称解密方法
* @param byteSource 需要解密的数据
* @return 经过解密的数据
* @throws Exception
*/
public static byte[] symmetricDecrypto(byte[] byteSource) throws Exception
{
ByteArrayOutputStream baos = new ByteArrayOutputStream();
try
{
int mode = Cipher.DECRYPT_MODE;
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("DES");
byte[] keyData = {1, 9, 8, 2, 0, 8, 2, 1};
DESKeySpec keySpec = new DESKeySpec(keyData);
Key key = keyFactory.generateSecret(keySpec);
Cipher cipher = Cipher.getInstance("DES");
cipher.init(mode, key);
int blockSize = cipher.getBlockSize();
int position = 0;
int length = byteSource.length;
boolean more = true;
while(more)
{
if(position + blockSize <= length)
{
baos.write(cipher.update(byteSource, position, blockSize));