一个用JAVA开发的会话密钥程序

/*
运行本程序你需要下载JCE，Bouncy Castle的JCE with Provider and Lightweight API
网址是 http://www.bouncycastle.org
配置如下：
在WINDOWS中，你需要把下载的bcprov-jdk14-119.jar文件拷贝到两个地方：
一个在你安装的JDK目录中，比如说我的是C:\j2sdk1.4.0-rc\jre\lib\ext
另一个在你的JDK运行环境中，我的是在
C:\Program Files\Java\j2re1.4.0-rc\lib\ext；
另外还要在对两个java.security进行修改：
我的在 C:\j2sdk1.4.0-rc\jre\lib\security\java.security；
C:\Program Files\Java\j2re1.4.0-rc\lib\security\java.security;
在java.security中加入 security.provider.6=org.bouncycastle.jce.provider.BouncyCastleProvider
如果一切顺利，你就可以运行本程序了。

该程序具有对你的文件加解密功能。需要你指定的数据，程序中已给了接口。
比如说你指定了要加密的文件名"4.txt",加密后的文件存放位置"6.txt",
还有口令password如"liufeng"后，运行该程序，那么"6.txt" 中将是"4.txt"的密文。
注意口令是解密的钥匙，不要忘记。
其他解密过程自己参考。

本程序利用会话密钥加密，提供很多接口。如果你项目中需要加密过程，可以稍加改进为你所用
*/
import java.security.*;
import java.security.spec.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.io.*;
import java.util.*;


public class FileEncryptorRSA {


private static final int ITERATIOnS=1000;//计算次数，在加盐中用到
private static byte[] publicKeyBytes;//公钥
private static byte[] privateKeyBytes;//私钥
private static String SessionKey;//会话密钥
public static String ENCRYPT_PRIVATEKEY_FILE="1.txt";//该文件放置加密的私钥
private static String TEXT_FILE="4.txt";//要加密的文件
private static String ENCRPTOR_TEXT_FILE="5.txt";//被加密后的文件
private static String DENCRYPTOR_TEXT_FILE="6.txt";//解密后的文件
private static String password="liufeng";//口令用于加密私钥


public void setTEXT_FILE(String fileName){
TEXT_FILE=fileName;
}
public void setENCRYPT_PRIVATEKEY_FILE(String fileName){
ENCRYPT_PRIVATEKEY_FILE=fileName;
}
public String getENCRYPT_PRIVATEKEY_FILE(){
return ENCRYPT_PRIVATEKEY_FILE;
}

public void setENCRPTOR_TEXT_FILE(String fileName){
ENCRPTOR_TEXT_FILE=fileName;
}
public String getENCRPTOR_TEXT_FILE(){
return ENCRPTOR_TEXT_FILE;
}
public void setDENCRYPTOR_TEXT_FILE(String fileName){
DENCRYPTOR_TEXT_FILE=fileName;
}
public String getDENCRYPTOR_TEXT_FILE(){
return DENCRYPTOR_TEXT_FILE;
}
public void setPassword(String password){
this.password=password;
}


//create a RSA secretKey
public static void createKey()throws Exception{
KeyPairGenerator keyPairGenerator=KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(1024);
KeyPair keyPair=keyPairGenerator.genKeyPair();
//得到公钥的字节数组
publicKeyBytes=keyPair.getPublic().getEncoded();
//得到私钥
byte[] privateKeyBytes=keyPair.getPrivate().getEncoded();
byte[] encrytedPrivatekey=passwordEncrypt(password.toCharArray(),privateKeyBytes);
FileOutputStream fos=new FileOutputStream(ENCRYPT_PRIVATEKEY_FILE);
fos.write(encrytedPrivatekey);
fos.close();
}



//通过给的口令加密私钥
private static byte[] passwordEncrypt(char[] password,byte[] privateKeyBytes)
throws Exception{
//create 8 byte salt
byte[] salt=new byte[8];
Random random=new Random();
random.nextBytes(salt);
//create a PBE key and cipher
PBEKeySpec keySpec=new PBEKeySpec(password);
SecretKeyFactory keyFactory=SecretKeyFactory.getInstance("PBEWithSHAAndTwofish-CBC");
SecretKey key=keyFactory.generateSecret(keySpec);
PBEParameterSpec paramSpec=new PBEParameterSpec(salt,ITERATIONS);
Cipher cipher=Cipher.getInstance("PBEWithSHAAndTwofish-CBC");
cipher.init(Cipher.ENCRYPT_MODE,key,paramSpec);
//Encrypt the byte[]
byte[] cipherPriKey=cipher.doFinal(privateKeyBytes);
//write out salt ,and then the cipherPriKey
ByteArrayOutputStream baos=new ByteArrayOutputStream();
baos.write(salt);
baos.write(cipherPriKey);
return baos.toByteArray();
}



//用会话密钥加密给定的文件，然后用公钥加密会话密钥，并存入文件中
//最后加密后的文件由密钥长度+已加密的密钥（会话密钥）+密文
public static void encrypt()throws Exception{

//转换成RSA密钥
X509EncodedKeySpec keySpec=new X509EncodedKeySpec(publicKeyBytes);
KeyFactory keyFactory=KeyFactory.getInstance("RSA");
PublicKey publickey=keyFactory.generatePublic(keySpec);
//打开存贮密文的文件
DataOutputStream output=new DataOutputStream(new FileOutputStream(ENCRPTOR_TEXT_FILE));
//创建RSA的CIpher
Cipher rsaCipher=Cipher.getInstance("RSA/ECB/PKCS1Padding");
rsaCipher.init(Cipher.ENCRYPT_MODE,publickey);
//创建会话密钥(Rijndael)
KeyGenerator rijndaelKeyGenerator=KeyGenerator.getInstance("Rijndael");
rijndaelKeyGenerator.init(256);
Key rijndaelKey=rijndaelKeyGenerator.generateKey();
//公钥加密会话密钥
byte[] encodedKeyBytes=rsaCipher.doFinal(rijndaelKey.getEncoded());
output.writeInt(encodedKeyBytes.length);
output.write(encodedKeyBytes);
//产生IV向量
SecureRandom random=new SecureRandom();
byte[] iv=new byte[16];
random.nextBytes(iv);
output.write(iv);

//加密正文
IvParameterSpec spec=new IvParameterSpec(iv);
Cipher symmetricCipher=Cipher.getInstance("Rijndael/CBC/PKCS5Padding");
symmetricCipher.init(Cipher.ENCRYPT_MODE,rijndaelKey,spec);
CipherOutputStream cos=new CipherOutputStream(output,symmetricCipher);
FileInputStream input=new FileInputStream(TEXT_FILE);

int theByte=0;
while((theByte=input.read())!=-1){
cos.write(theByte);
}
input.close();
cos.close();
return;
}



//得到私钥
private static byte[] passwordDecrypt(char[] password,byte[] ciphertext)
throws Exception{
byte[] salt=new byte[8];
ByteArrayInputStream bais=new ByteArrayInputStream(ciphertext);
bais.read(salt,0,8);
byte[] remainingCiphertext=new byte[ciphertext.length-8];
bais.read(remainingCiphertext,0,ciphertext.length-8);
PBEKeySpec keySpec=new PBEKeySpec(password);
SecretKeyFactory keyFactory=SecretKeyFactory.getInstance("PBEWithSHAAndTwofish-CBC");
SecretKey key=keyFactory.generateSecret(keySpec);
PBEParameterSpec paramSpec=new PBEParameterSpec(salt,ITERATIONS);
Cipher cipher=Cipher.getInstance("PBEWithSHAAndTwofish-CBC");
cipher.init(Cipher.DECRYPT_MODE,key,paramSpec);
return cipher.doFinal(remainingCiphertext);
}


//解密加密的文件
public static void decrypt()
throws Exception{
FileInputStream fis=new FileInputStream(ENCRYPT_PRIVATEKEY_FILE);
ByteArrayOutputStream baos=new ByteArrayOutputStream();
int theByte=0;
while((theByte=fis.read())!=-1){
baos.write(theByte);
}
fis.close();
//得到被加密的私钥
byte[] keyBytes=baos.toByteArray();
baos.close();
//得到私钥
byte[] sKey=passwordDecrypt(password.toCharArray(),keyBytes);
//产生RSA私钥
PKCS8EncodedKeySpec keySpec=new PKCS8EncodedKeySpec(sKey);
KeyFactory keyFactory=KeyFactory.getInstance("RSA");
PrivateKey privateKey=keyFactory.generatePrivate(keySpec);
Cipher rsaCipher=Cipher.getInstance("RSA/ECB/PKCS1Padding");

DataInputStream dis=new DataInputStream(new FileInputStream(ENCRPTOR_TEXT_FILE));
//读密文中密码长度和密码
byte[] encryptedKeyBytes=new byte[dis.readInt()];
dis.readFully(encryptedKeyBytes);
rsaCipher.init(Cipher.DECRYPT_MODE,privateKey);
byte[] rijdaelKeyBytes=rsaCipher.doFinal(encryptedKeyBytes);
//得到会话密钥
SecretKey rijndaelKey=new SecretKeySpec(rijdaelKeyBytes,"Rijndael");
byte[] iv=new byte[16];
dis.read(iv);
IvParameterSpec spec=new IvParameterSpec(iv);
//用会话密钥解密正文
Cipher cipher=Cipher.getInstance("Rijndael/CBC/PKCS5Padding");
cipher.init(Cipher.DECRYPT_MODE,rijndaelKey,spec);

CipherInputStream cis=new CipherInputStream(dis,cipher);
FileOutputStream fos=new FileOutputStream(DENCRYPTOR_TEXT_FILE);

theByte=0;
while((theByte=cis.read())!=-1){
fos.write(theByte);
}
cis.close();
fos.close();
return;
}
public static void main(String[] args)throws Exception{
createKey();
encrypt();
decrypt();
}
}