Java安全（JCA/JSSE）：对称加密
得到一个类的实例,一般有这些方法：
New
本类. getInstance() Cipher. getInstance(“AES”)
其他类的某个方法产生 Connectionct=DriverManager.getConnection()
工厂类的产生方法
ServerSocket ss= ServerSocketFactory.getDefault().createServerSocket()
关于密钥加密加密和流的一些小算法
//把key写入文件给别//人
package com.xiongshiyan.security;
import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.security.Key;
import java.security.NoSuchAlgorithmException;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKeyFactory;
publicclass SecretKeyTest {
/**
* @param args
* @throwsNoSuchPaddingException
* @throwsNoSuchAlgorithmException
*/
publicstaticvoid main(String[] args) throws Exception {
// TODO Auto-generatedmethod stub
SecretKeyTest.secretAES();
//SecretKeyTest.deSecretAES();
}
privatestaticvoid secretAES() throws Exception{
//创建加密对象
Cipher cipher = Cipher.getInstance("AES");
//Keykey=SecretKeyFactory.getInstance("AES").generateSecret(null);
Key key=KeyGenerator.getInstance("AES").generateKey();
cipher.init(Cipher.ENCRYPT_MODE, key);
byte[] secResult=cipher.doFinal("abcdefg数据".getBytes());
System.out.println(new String(secResult));
//把加密后的数据和key一起给别人 别人拿到了之后进行恢复
ObjectOutputStream oosKey=new ObjectOutputStream(new FileOutputStream("key.key"));
oosKey.writeObject(key);//写入加密key
oosKey.close();
FileOutputStream oosDat=new FileOutputStream("dat.dat");
oosDat.write(secResult);//写入加密dat
oosDat.close();
}
privatestaticvoid deSecretAES() throws Exception{
//创建加密对象
Cipher cipher = Cipher.getInstance("AES");
/**
* 实现Serializable接口，保存数据的时候你就能按照sun定义的标准格式进行，ObjectInputStream和ObjectOutputStream提供的readObject和writeObject进行读写，你也可以自己扩展格式，实现Externalizable接口
*/
ObjectInputStream oisKey=new ObjectInputStream(new FileInputStream("key.key"));
Keykey=(Key)oisKey.readObject();
oisKey.close();
cipher.init(Cipher.DECRYPT_MODE, key);
FileInputStream fisDat=new FileInputStream("dat.dat");
/* ByteArrayOutputStreambaos=new ByteArrayOutputStream();
SecretKeyTest.copyStream(fisDat, baos);
byte[] deSecResult=cipher.doFinal(baos.toByteArray());*/
byte[] src=newbyte[fisDat.available()];//对于文件流来说就是其长度，而对于像网络流就不是了
int len=fisDat.read(src);
int total=0;
while(total<src.length){
total+=len;
len=fisDat.read(src, total, src.length-total);
}
byte[] deSecResult=cipher.doFinal(src);
fisDat.close();
System.out.println(new String(deSecResult));
}
privatestaticvoid copyStream(InputStream is,OutputStream os) throws Exception{
byte[] buff=newbyte[1024];
int total=0;
int len=is.read(buff);
while(len!=-1){
os.write(buff, 0, len);
len=is.read(buff);
}
}
}
//脑袋里面记住一个密码就好了
privatestaticvoid secretPBE() throws Exception{//脑袋里面记住你的密码
//创建加密对象
Cipher cipher = Cipher.getInstance("PBEWithMD5AndDES");
Key key=SecretKeyFactory.getInstance("PBEWithMD5AndDES")
.generateSecret(new PBEKeySpec("xiongshiyan".toCharArray()));//xiongshiyan就是你的密码
//Keykey=KeyGenerator.getInstance("AES").generateKey();
PBEParameterSpec pbeParameterSpec=new PBEParameterSpec(newbyte[]{1,2,3,4,5,6,7,8},1000);
cipher.init(Cipher.ENCRYPT_MODE,key,pbeParameterSpec);
byte[] secResult=cipher.doFinal("数据abcdefg".getBytes());
System.out.println(new String(secResult));
FileOutputStream oosDat=new FileOutputStream("dat.dat");
oosDat.write(secResult);//写入加密dat
oosDat.close();
}
privatestaticvoid deSecretPBE() throws Exception{
Cipher cipher = Cipher.getInstance("PBEWithMD5AndDES");
Key key=SecretKeyFactory.getInstance("PBEWithMD5AndDES")
.generateSecret(new PBEKeySpec("xiongshiyan".toCharArray()));
//Keykey=KeyGenerator.getInstance("AES").generateKey();
PBEParameterSpec pbeParameterSpec=new PBEParameterSpec(newbyte[]{1,2,3,4,5,6,7,8},1000);
cipher.init(Cipher.DECRYPT_MODE,key,pbeParameterSpec);
FileInputStream fisDat=new FileInputStream("dat.dat");
/* ByteArrayOutputStreambaos=new ByteArrayOutputStream();
SecretKeyTest.copyStream(fisDat, baos);
byte[] deSecResult=cipher.doFinal(baos.toByteArray());*/
byte[] src=newbyte[fisDat.available()];//对于文件流来说就是其长度，而对于像网络流就不是了
int len=fisDat.read(src);
int total=0;
while(total<src.length){
total+=len;
len=fisDat.read(src, total, src.length-total);
}
byte[] deSecResult=cipher.doFinal(src);
fisDat.close();
System.out.println(new String(deSecResult));
}