JDK中對稱加密DES

數據加密算法（Data Encryption Algorithm，DEA）是一種對稱加密算法，很可能是使用最廣泛的密鑰系統，特別是在保護金融數據的安全中，最初開發的DEA是嵌入硬件中的。通常，自動取款機（Automated Teller Machine，ATM）都使用DEA。它出自IBM的研究工作，IBM也曾對它擁有幾年的專利權，但是在1983年已到期後，處於公有範圍中，允許在特定條件下可以免除專利使用費而使用。1997年被美國政府正式採納

demo如下：

package com.zhangfx.jiami.des;

import java.security.Key;
import java.security.NoSuchAlgorithmException;
import java.security.Security;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

import org.bouncycastle.jce.provider.BouncyCastleProvider;

/**
 * 密鑰長度爲56位和64位
 * 1998年後不斷被破解，不再使用
 * @author ambitious
 *
 */
public class AmbitiousDES {
	
	private static String str ="ambitious security des";
	
	public static void main(String[] args){
		jdkDES();
		bcDES();
	}
	
	
	public static void jdkDES(){
		try {
			
			//生成key
			KeyGenerator keyGenerator = KeyGenerator.getInstance("DES");
			keyGenerator.init(56);
			SecretKey  secretKey = keyGenerator.generateKey();
			byte[] byteKey =  secretKey.getEncoded();
			
			//key的轉換
			DESKeySpec dESKeySpec = new DESKeySpec(byteKey);
			SecretKeyFactory factory =  SecretKeyFactory.getInstance("DES");//制定加密方式
			Key convertsecretKey =  factory.generateSecret(dESKeySpec);
			
			//加密
			Cipher  cipher  = Cipher.getInstance("DES/ECB/PKCS5Padding");//  加解密的算法/工作方式/填充方式
			cipher.init(Cipher.ENCRYPT_MODE, convertsecretKey);
			byte[] result = cipher.doFinal(str.getBytes());
			System.out.println("jdk dsc 16進制的結果 encrypt:"+CHexConver.byte2HexStr(result));
			
			//解密
			cipher.init(Cipher.DECRYPT_MODE, convertsecretKey);
			result = cipher.doFinal(result);
			System.out.println("jdk dsc decrypt:"+new String(result));
			
		} catch (Exception e) {
			e.printStackTrace();
		}
	}
	
	
	
	
	public static void bcDES(){

		try {
			Security.addProvider(new BouncyCastleProvider());			
			//生成key
			KeyGenerator keyGenerator = KeyGenerator.getInstance("DES","BC");
			keyGenerator.init(56);
			keyGenerator.getProvider();
			SecretKey  secretKey = keyGenerator.generateKey();
			byte[] byteKey =  secretKey.getEncoded();
			
			//key的轉換
			DESKeySpec dESKeySpec = new DESKeySpec(byteKey);
			SecretKeyFactory factory =  SecretKeyFactory.getInstance("DES");//制定加密方式
			Key convertsecretKey =  factory.generateSecret(dESKeySpec);
			
			//加密
			Cipher  cipher  = Cipher.getInstance("DES/ECB/PKCS5Padding");//  加解密的算法/工作方式/填充方式
			cipher.init(Cipher.ENCRYPT_MODE, convertsecretKey);
			byte[] result = cipher.doFinal(str.getBytes());
			System.out.println("jdk dsc 16進制的結果 encrypt:"+CHexConver.byte2HexStr(result));
			
			//解密
			cipher.init(Cipher.DECRYPT_MODE, convertsecretKey);
			result = cipher.doFinal(result);
			System.out.println("jdk dsc decrypt:"+new String(result));
			
		} catch (Exception e) {
			e.printStackTrace();
		}
	
		
	}

}