/// <summary>
/// Decrypt
/// </summary>
/// <param name="cipherText"></param>
/// <param name="key"></param>
/// <returns></returns>
public static string Decrypt(string cipherText, string key)
{
string clearText = "";
var md5Str = Md5EncryptionTool.Encrypt(key);
var endChar = cipherText[cipherText.Length - 1]; // 取出密文最后一个字符, 即混淆前缀字符数
int prefixNum = Convert.ToInt32(endChar.ToString(), 10);
var cipherText1 = cipherText.Substring(prefixNum, cipherText.Length - prefixNum - 1);
var indexStart = DateTime.Now.Day;
var len = cipherText1.Length;
for (var i = 0; i < len; i++)
{
int index = (indexStart + i) >= 32 ? (indexStart + i - 32) : (indexStart + i);
var ch = cipherText1[i];
var ch1 = md5Str[index];
byte newByte = (byte)((byte)ch - (byte)ch1);
clearText += (char)newByte;
}
return(clearText);
}
/// <summary>
/// Encrypt
/// </summary>
/// <param name="clearText"></param>
/// <param name="key"></param>
/// <returns></returns>
public static string Encrypt(string clearText, string key)
{
string cipherText = "";
if (clearText.Length >= 6)
{
string md5Str = Md5EncryptionTool.Encrypt(key);
var indexStart = DateTime.Now.Day;
string cipherText1 = "";
for (int i = 0; i < clearText.Length; i++)
{
int index = (indexStart + i) >= 32 ? (indexStart + i - 32) : (indexStart + i);
byte ch = (byte)clearText[i];
byte ch1 = (byte)md5Str[index];
byte newByte = (byte)(ch + ch1);
cipherText1 += (char)newByte;
}
string prefix = "";
int ran = RandTool.CreateRandValWithMinMax(6, 10);
for (int i = 0; i < ran; i++)
{
int ran1 = RandTool.CreateRandValWithMinMax(0, 31);
prefix += md5Str[ran1];
}
string suffix = ran.ToString();
cipherText = string.Format("{0}{1}{2}", prefix, cipherText1, suffix);
}
else
{
cipherText = "";
}
return(cipherText);
}
