using System;
namespace Penguin.Library.Security
{
/// <summary>
/// Cryptography 加密/解密
/// </summary>
public class Cryptography
{
public Cryptography ()
{ }
private static char[] key = "yA36zA48dEhfrvghGRg57h5UlDv3".ToCharArray();
// FlashFXP 的解密方法
/// <summary>
/// 解密方法
/// </summary>
/// <param name="x">密文</param>
/// <returns>明文</returns>
public static string Decrypt(string x)
{
System.Text.StringBuilder sb = new System.Text.StringBuilder();
char[] ca = x.ToCharArray();
for (int i = 0; i < (ca.Length - 2); i += 2)
{
string s1 = "" + ca[i + 2] + ca[i + 3];
string s2 = "" + System.Convert.ToString((byte) key[(i / 2) % 13], 16);
string s3 = "" + ca[i] + ca[i + 1];
int m = (System.Convert.ToInt32(s1, 16) ^ System.Convert.ToInt32(s2, 16)) - System.Convert.ToInt32(s3, 16);
if (m < 0)
{
m += 255;
}
sb.Append((char) ((short) m));
}
return sb.ToString();
}
// FlashFXP 的加密方法
/// <summary>
/// 加密方法
/// </summary>
/// <param name="x">明文</param>
/// <returns>密文</returns>
public static string Encrypt(string x)
{
char[] ca = x.ToCharArray();
int k = new System.Random().Next(255);
System.Text.StringBuilder sb = null;
if (k > 15)
{
sb = new System.Text.StringBuilder("" + System.Convert.ToString(k, 16));
}
else
{
sb = new System.Text.StringBuilder("0" + System.Convert.ToString(k, 16));
}
int m = System.Convert.ToInt32(sb.ToString(), 16);
for (int i = 0; i < ca.Length; i++)
{
if ((ca[i] + m) > 255)
{
m = ((ca[i] + m) - 255) ^ key[i % 13];
}
else
{
m = (ca[i] + m) ^ key[i % 13];
}
if (m > 15)
{
sb.Append(System.Convert.ToString(m, 16));
}
else
{
sb.Append("0" + System.Convert.ToString(m, 16));
}
}
return sb.ToString().ToUpper();
}
}
}
