web字符串加密解密方法

using System;

using System.Text;

using System.Security;

using System.Web.Security;

namespace StringOperation

{

/// <summary>

/// StringOperation 的摘要说明。

/// </summary>

public class StringOperation

{

public StringOperation()

{

//

// TODO: 在此处添加构造函数逻辑

//

}

/// <summary>

/// 转换特殊字符

/// </summary>

/// <param name="str">待转换的字符</param>

/// <returns></returns>

public static string Encode(string str)

{

str = str.Replace("&","&");

str = str.Replace("'","''");

str = str.Replace("\"",""");

str = str.Replace(" "," ");

str = str.Replace("<","<");

str = str.Replace(">",">");

str = str.Replace("\n","<br>");

return str;

}

/// <summary>

/// decode

/// </summary>

/// <param name="str">string</param>

/// <returns></returns>

public static string Decode(string str)

{

str = str.Replace("<br>","\n");

str = str.Replace(">",">");

str = str.Replace("<","<");

str = str.Replace(" "," ");

str = str.Replace(""","\"");

return str;

}

/// <summary>

/// encrypting string

/// </summary>

/// <returns></returns>

public static string Encrypt(string Password)

{

string str = "";

FormsAuthenticationTicket ticket = new System.Web.Security.FormsAuthenticationTicket(Password,true,2);

str = FormsAuthentication.Encrypt(ticket).ToString();

return str;

}

/// <summary>

/// encrypting string

/// </summary>

/// <param name="Password">encrypting string</param>

/// <param name="Format">format,0 is SHA1,1 is MD5</param>

/// <returns></returns>

public static string Encrypt(string Password,int Format)

{

string str = "";

switch(Format)

{

case 0:

str = FormsAuthentication.HashPasswordForStoringInConfigFile(Password,"SHA1");

break;

case 1:

str = FormsAuthentication.HashPasswordForStoringInConfigFile(Password,"MD5");

break;

}

return str;

}

/// <summary>

/// decrypt string

/// </summary>

/// <param name="Passowrd">encrypted string</param>

/// <returns></returns>

public static string Decrypt(string Passowrd)

{

string str="";

str= FormsAuthentication.Decrypt(Passowrd).Name.ToString();

return str;

}

/// <summary>

/// Encrypt Cookie

/// </summary>

/// <param name="str">Target cookie string</param>

/// <returns></returns>

public static string EncryptCookie(string strCookie,int type)

{

string str=En(strCookie,type);

StringBuilder sb = new StringBuilder();

foreach(char a in str)

{

sb.Append(Convert.ToString(a,16).PadLeft(4,'0'));

}

return sb.ToString();

}

/// <summary>

/// Decrypt Cookie

/// </summary>

/// <param name="str">Target cookie string</param>

/// <returns></returns>

public static string DecryptCookie(string strCookie,int type)

{

StringBuilder sb = new StringBuilder();

string [] strarr = new String[255];

int i,j,count=strCookie.Length/4;

string strTmp;

for(i=0;i<count;i++)

{

for(j=0;j<4;j++)

{

sb.Append(strCookie.Substring(i*4+j,1));

}

strarr[i] = sb.ToString();

sb.Remove(0,sb.Length);

}

for(i=0;i<count;i++)

{

strTmp = uint.Parse(strarr[i],System.Globalization.NumberStyles.AllowHexSpecifier).ToString("D");

char ch = (char)uint.Parse(strTmp);

sb.Append(ch);

}

return De(sb.ToString(),type);

}

private static string En(string strCookie,int type)

{

string str;

if(type % 2==0)

{

str = Transform1(strCookie);

}

else

{

str = Transform3(strCookie);

}

str = Transform2(strCookie);

return str;

}

private static string De(string strCookie,int type)

{

string str;

if(type % 2==0)

{

str = DeTransform1(strCookie);

}

else

{

str = DeTransform3(strCookie);

}

str = Transform2(strCookie);

return str;

}

/// <summary>

/// methods 1

/// </summary>

/// <param name="str">string</param>

/// <returns>decrypted string</returns>

public static string DeTransform1(string str)

{

int i=0;

StringBuilder sb = new StringBuilder();

foreach(char a in str)

{

switch(i % 6)

{

case 0:

sb.Append((char)(a-1));

break;

case 1:

sb.Append((char)(a-5));

break;

case 2:

sb.Append((char)(a-7));

break;

case 3:

sb.Append((char)(a-2));

break;

case 4:

sb.Append((char)(a-4));

break;

case 5:

sb.Append((char)(a-9));

break;

}

i++;

}

return sb.ToString();

}

/// <summary>

/// method1

/// </summary>

/// <param name="str">string</param>

/// <returns>encrypted string</returns>

public static string Transform1(string str)

{

int i=0;

StringBuilder sb = new StringBuilder();

foreach(char a in str)

{

switch(i % 6)

{

case 0:

sb.Append((char)(a+1));

break;

case 1:

sb.Append((char)(a+5));

break;

case 2:

sb.Append((char)(a+7));

break;

case 3:

sb.Append((char)(a+2));

break;

case 4:

sb.Append((char)(a+4));

break;

case 5:

sb.Append((char)(a+9));

break;

}

i++;

}

return sb.ToString();

}

/// <summary>

/// method1

/// </summary>

/// <param name="str">string</param>

/// <returns>encrypted string</returns>

public static string Transform2(string str)

{

uint j=0;

StringBuilder sb = new StringBuilder();

str=Reverse(str);

foreach(char a in str)

{

j=a;

if(j>255)

{

j=(uint)((a>>8) + ((a&0x0ff)<<8));

}

else

{

j=(uint)((a>>4) + ((a&0x0f)<<4));

}

sb.Append((char)j);

}

return sb.ToString();

}

/// <summary>

/// methods 1

/// </summary>

/// <param name="str">string</param>

/// <returns>decrypted string</returns>

public static string DeTransform3(string str)

{

int i=0;

StringBuilder sb = new StringBuilder();

foreach(char a in str)

{

switch(i % 6)

{

case 0:

sb.Append((char)(a-3));

break;

case 1:

sb.Append((char)(a-6));

break;

case 2:

sb.Append((char)(a-8));

break;

case 3:

sb.Append((char)(a-7));

break;

case 4:

sb.Append((char)(a-5));

break;

case 5:

sb.Append((char)(a-2));

break;

}

i++;

}

return sb.ToString();

}

/// <summary>

/// method1

/// </summary>

/// <param name="str">string</param>

/// <returns>encrypted string</returns>

public static string Transform3(string str)

{

int i=0;

StringBuilder sb = new StringBuilder();

foreach(char a in str)

{

switch(i % 6)

{

case 0:

sb.Append((char)(a+3));

break;

case 1:

sb.Append((char)(a+6));

break;

case 2:

sb.Append((char)(a+8));

break;

case 3:

sb.Append((char)(a+7));

break;

case 4:

sb.Append((char)(a+5));

break;

case 5:

sb.Append((char)(a+2));

break;

}

i++;

}

return sb.ToString();

}

/// <summary>

/// 将指定的字符反过来显示

/// </summary>

/// <param name="str">待反转的字符</param>

/// <returns>反转后的字符</returns>

public static string Reverse(string str)

{

int i;

StringBuilder sb = new StringBuilder();

for(i=str.Length-1;i>=0;i--)

{

sb.Append(str[i]);

}

return sb.ToString();

}

}

}