?package myitem.encrypt;

/*數據加密、解密*/

import java.security.*;

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

/*字符串加密工具集合*/

public class Encrypt{
	private static final String PASSWORD_CRYPT_KEY = "webkaidi";
	private final static String DES = "DES";

	/*加密*/
	//參數說明：數據源（進行加密的數據），密鑰（長度必須是8的倍數）
	public static byte[] encrypt(byte[] source, byte[] key)throws Exception{
		//DES算法要求有一個可信任的隨機數源
        SecureRandom sr = new SecureRandom();
        //從原始密匙數據創建DESKeySpec對象
        DESKeySpec dks = new DESKeySpec(key);
        //創建一個密匙工廠
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        //利用密鑰工廠把DESKeySpec轉換成一個SecretKey對象
        SecretKey securekey = keyFactory.generateSecret(dks);
        //Cipher對象實際完成加密操作
        Cipher cipher = Cipher.getInstance(DES);
        //用密匙初始化Cipher對象
        cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
        //現在，獲取數據并加密
        //正式執行加密操作
        return cipher.doFinal(source);
	}

	/*加密*/
	//參數說明：數據源（加密的數據），密鑰（長度必須是8的倍數）
	public static byte[] decrypt(byte[] source, byte[] key)throws Exception{
		//DES算法要求有一個可信任的隨機數源
        SecureRandom sr = new SecureRandom();
        //從原始密匙數據創建DESKeySpec對象
        DESKeySpec dks = new DESKeySpec(key);
        //創建一個密匙工廠
        SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
        //利用密鑰工廠把DESKeySpec轉換成一個SecretKey對象
        SecretKey securekey = keyFactory.generateSecret(dks);
        //Cipher對象實際完成解密操作
        Cipher cipher = Cipher.getInstance(DES);
        //用密匙初始化Cipher對象
        cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
        //現在，獲取數據并解密
        // 正式執行解密操作
        return cipher.doFinal(source);
	}

	/*數據加密*/
	//參數說明：需加密的字符串
	public final static String encrypt(String str){
		try{
			return ByteTHex(encrypt(str.getBytes(),PASSWORD_CRYPT_KEY.getBytes()));
		}catch(Exception e){
			
		}
		return null;
	}

	/*數據加密*/
	//參數說明：需解密的字符串
	public final static String decrypt(String str){
		try{
			return new String(decrypt(HexTByte(str.getBytes()),
					PASSWORD_CRYPT_KEY.getBytes())); 
		}catch(Exception e){
			
		}
		return null;
	}

	/*二進制轉換為字符串*/
	//參數說明：需要進行轉換的二進制
	public static String ByteTHex(byte[] b){
		String hs = "";
        String stmp = "";

        for(int n=0; n<b.length; n++){
        	stmp = (java.lang.Integer.toHexString(b[n]&0XFF));
        	if(stmp.length() == 1){
                hs = hs+"0"+stmp;
        	}else{
                hs = hs+stmp;
        	}
        }
        return hs.toUpperCase();
	}

	public static byte[] HexTByte(byte[] b){
		if((b.length%2)!=0){
			
		}
		byte[] Byte = new byte[b.length/2];
		for(int n=0; n<b.length; n+=2){
             String item = new String(b,n,2);
             Byte[n/2] = (byte)Integer.parseInt(item,16);
        }
		return Byte;
	}
}