package com.yihu.wlyy.util;

/**
 * Riva双向加密,解密算法实现
 * @author huangwenjie
 * @date 2018/1/27 14:36
 */
public class RivaEDCode {
	/**
	 * 16进制转换成10进制
	 *
	 * @param hexString 要进行转换的16进制数字字符串
	 * @return Sring
	 * @throws Exception
	 */
	public static String hextoString(String hexString)
	{
		
		String hexStr = "";
		
		int i;
		int k = 0;
		
		int str1 = 0;
		int str2 = 0;
		
		// 每次取得两个16进制数字字符
		char str3 = hexString.charAt(0);
		char str4 = hexString.charAt(1);
		
		// 定义16进制字符所对应的数值,每个16进制数值对应为数组的索引值
		char myarray[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
		
		for(i = 0; i < myarray.length; i++)
		{
			// 对应16进制字符所对应的数值
			if(myarray[i] == str3)
			{
				str1 = i;
			}
			
			if(myarray[i] == str4)
			{
				str2 = i;
			}
		}
		
		// 换算成10进制数字
		k = str1 * 16 + str2;
		
		hexStr = Integer.toString(k);
		
		return hexStr;
	}
	
	/**
	 * @param encode_str1 字符串一
	 * @param encode_str2 需要加密的字符串
	 * @return String 加密后的字符串
	 * @throws Exception
	 */
	public static String uncPassEncode(String encode_str1, String encode_str2)
	{
		
		String passString = "";
		
		String str = "";
		int userLens = encode_str1.length();
		int passLens = encode_str2.length();
		
		int userPos = 0;
		int passPos = 0;
		
		while (passPos < passLens)
		{
			
			char acii1 = encode_str2.charAt(passPos);
			char acii2 = encode_str1.charAt(userPos);
			
			str += Integer.toHexString(acii1 + acii2);
			userPos++;
			
			if(userPos >= userLens)
				userPos = 0;
			passPos++;
		}
		
		passString = str.toUpperCase();
		
		return passString;
	}
	
	
	/**
	 * 解密用riva加密算法加密的字符串
	 *
	 * @param encode_str1 字符串
	 * @param encode_str2 需要解密的密文
	 * @return String 解密的明文
	 * @throws Exception
	 * @throws NumberFormatException
	 * @throws Exception
	 */
	public static String uncPassDecode(String encode_str1, String encode_str2)
	{
		
		String decodePassStr = "";
		// String en1;
		// String en2;
		
		int userLens = encode_str1.length();
		int passLens = encode_str2.length();
		
		int userPos = 0;
		int passPos = 0;
		
		while (passPos < passLens - 1)
		{

            /*
             * 16进制转换成10进制
             */
			int str1 = Integer.parseInt(hextoString(encode_str2.substring(passPos, passPos + 2)));
			
			int str2 = encode_str1.charAt(userPos);
			
			decodePassStr += String.valueOf((char)(str1 - str2));
			
			userPos++;
			
			if(userPos >= userLens)
				userPos = 0;
			
			passPos += 2;
		}
		
		return decodePassStr;
	}
	
	/**
	 * 双重解密riva算法加密的密文
	 *
	 * @param str1 字符串1
	 * @param str2 字符串2
	 * @param key 加密的密文
	 * @return String 解密后的明文
	 * @throws Exception
	 */
	public static String passDecode(String str1, String str2, String key)
	{
		
		return uncPassDecode(str1, uncPassDecode(str2, key));
		
	}
	
	/**
	 * 利用riva加密算法双重加密字符串
	 *
	 * @param str1 字符串1
	 * @param key 需要加密字符串
	 * @param str2 字符串2
	 * @return String 经过加密的字符串
	 * @throws Exception
	 */
	public static String passEncode(String str1, String str2, String key)
	{
		
		return uncPassEncode(str2, uncPassEncode(str1, key));
		
	}
	
	
	//测试-加密解密
	public static void main(String[] args)
	{
		//解密
//		System.out.println(RivaEDCode.passDecode("LUZ7TN3KOT8AWCD3ZA4NBMI5VNF7E50F6XYEP2WZM68JQYY5JE02L4L5FS9R4NGUGMHSCAPW9AL","C3SHUI8OWBOA4ZASS7FEYJ6RIVXA9SW6U5OA56ERUYZTRFHCRZO8AHT4TTW2MAGT80MGXN","7A778B7F8D8D6E918F7B87756A9B"));
		
		//加密
//		System.out.println(RivaEDCode.passEncode("LUZ7TN3KOT8AWCD3ZA4NBMI5VNF7E50F6XYEP2WZM68JQYY5JE02L4L5FS9R4NGUGMHSCAPW9AL","C3SHUI8OWBOA4ZASS7FEYJ6RIVXA9SW6U5OA56ERUYZTRFHCRZO8AHT4TTW2MAGT80MGXN","1234567"));
	}
}