DES对称加密的实现及其源代码
package util;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import java.security.*;
import java.io.*;
/**
* Created by IntelliJ IDEA.
* User: Administrator
* Date: Dec 4, 2003
* Time: 9:29:19 PM
* To change this template use Options | File Templates.
*@author [email protected]
* 该类是加密处理类.主要用来对数据进行加密,解密操作.
*/
public class DESEncryptUtil {
/**
* 获得DES加密的密钥。在交易处理的过程中应该定时更
* 换密钥。需要JCE的支持，如果jdk版本低于1.4，则需要
* 安装jce-1_2_2才能正常使用。
* @return Key 返回对称密钥
* @throws java.security.NoSuchAlgorithmException
* @see util.EncryptUtil 其中包括加密和解密的方法
*/
public static Key getKey() throws NoSuchAlgorithmException {
Security.insertProviderAt(new com.sun.crypto.provider.SunJCE(), 1);
KeyGenerator generator = KeyGenerator.getInstance("DES");
generator.init(new SecureRandom());
Key key = generator.generateKey();
return key;
}
/**
* 将指定的数据根据提供的密钥进行加密
* @param key 密钥
* @param data 需要加密的数据
* @return byte[] 加密后的数据
* @throws util.EncryptException
*/
public static byte[] doEncrypt(Key key, byte[] data) throws EncryptException {
try {
//Get a cipher object
Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
//Encrypt
cipher.init(Cipher.ENCRYPT_MODE, key);
//byte[] stringBytes = amalgam.getBytes("UTF8");
byte[] raw = cipher.doFinal(data);
//BASE64Encoder encoder = new BASE64Encoder();
//String base64 = encoder.encode(raw);
return raw;
} catch (Exception e) {
e.printStackTrace();
throw new EncryptException("Do encrypt occurs Exception.[" + e.getMessage() + "]");
}
}
/**
* 将给定的已加密的数据通过指定的密钥进行解密
* @param key 密钥
* @param raw 待解密的数据
* @return byte[] 解密后的数据
* @throws util.EncryptException
*/
public static byte[] doDecrypt(Key key, byte[] raw) throws EncryptException {
try {
//Get a cipher object
Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
// Decrypt
cipher.init(Cipher.DECRYPT_MODE, key);
//BASE64Decoder decoder = new BASE64Decoder();
//byte[] raw = decoder.decodeBuffer(data);
byte[] data = cipher.doFinal(raw);
//String result = new String(stringBytes, "UTF8");
//System.out.println("the decrypted data is: " + result);
return data;
} catch (Exception e) {
e.printStackTrace();
throw new EncryptException("Do decrypt occurs Exception.[" + e.getMessage() + "]");
}
}
/**
* 得到一个密钥的密码
* @param key 密钥
* @param cipherMode 密码的类型
* @return Cipher
* @throws util.EncryptException 当加密出现异常情况时,产生异常信息
*/
public static Cipher getCipher(Key key, int cipherMode) throws EncryptException {
try {
Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
cipher.init(cipherMode, key);
return cipher;
} catch (Exception e) {
e.printStackTrace();
throw new EncryptException("Generate Cipher occurs Exception.[" + e.getMessage() + "]");
}
}
public static void main(String[] args) throws Exception {
Key key = DESEncryptUtil.getKey();
File file = new File("test.html");//随便找个文件发在当前运行目录下
FileInputStream in = new FileInputStream(file);
ByteArrayOutputStream bout = new ByteArrayOutputStream();
byte[] tmpbuf = new byte[1024];
int count = 0;
while ((count = in.read(tmpbuf)) != -1) {
bout.write(tmpbuf, 0, count);
tmpbuf = new byte[1024];
}
in.close();
byte[] orgData = bout.toByteArray();
byte[] raw = DESEncryptUtil.doEncrypt(key,orgData);
file = new File("encrypt_result.dat");
OutputStream out = new FileOutputStream(file);
out.write(raw);
out.close();
byte[] data = DESEncryptUtil.doDecrypt(key, raw);
file = new File("decrypt_result.html");
out = new FileOutputStream(file);
out.write(data);
out.flush();
out.close();
}
}