MD5加密解密類（asp.net）&使用MD5過時處理

加密類

#region ========加密========
/// <summary>
/// 加密
/// </summary>
/// <param name="Text"></param>
/// <returns></returns>
public static string Encrypt(string Text)
{
    return Encrypt(Text, "cong");
}
/// <summary> 
/// 加密數據 
/// </summary> 
/// <param name="Text"></param> 
/// <param name="sKey"></param> 
/// <returns></returns> 
public static string Encrypt(string Text, string sKey)
{
    DESCryptoServiceProvider des = new DESCryptoServiceProvider();
    byte[] inputByteArray;
    inputByteArray = Encoding.Default.GetBytes(Text);
    des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
    des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
    System.IO.MemoryStream ms = new System.IO.MemoryStream();
    CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write);
    cs.Write(inputByteArray, 0, inputByteArray.Length);
    cs.FlushFinalBlock();
    StringBuilder ret = new StringBuilder();
    foreach (byte b in ms.ToArray())
    {
        ret.AppendFormat("{0:X2}", b);
    }
    return ret.ToString();
}

#endregion


#region ========解密========


/// <summary>
/// 解密
/// </summary>
/// <param name="Text"></param>
/// <returns></returns>
public static string Decrypt(string Text)
{
    return Decrypt(Text, "cong");
}
/// <summary> 
/// 解密數據 
/// </summary> 
/// <param name="Text"></param> 
/// <param name="sKey"></param> 
/// <returns></returns> 
public static string Decrypt(string Text, string sKey)
{
    DESCryptoServiceProvider des = new DESCryptoServiceProvider();
    int len;
    len = Text.Length / 2;
    byte[] inputByteArray = new byte[len];
    int x, i;
    for (x = 0; x < len; x++)
    {
        i = Convert.ToInt32(Text.Substring(x * 2, 2), 16);
        inputByteArray[x] = (byte)i;
    }
    des.Key = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
    des.IV = ASCIIEncoding.ASCII.GetBytes(System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(sKey, "md5").Substring(0, 8));
    System.IO.MemoryStream ms = new System.IO.MemoryStream();
    CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write);
    cs.Write(inputByteArray, 0, inputByteArray.Length);
    cs.FlushFinalBlock();
    return Encoding.Default.GetString(ms.ToArray());
}

#endregion

 

在.net 4.5版本下，使用System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile進行MD5加密時，會出現已過時,如下圖：

MD5加密過時顯示.png

我們可以用下面的方法替代之：

命名空間:System.Web.Security程序集:System.Web（在 system.web.dll 中）

/// <summary>
/// 32位MD5加密
/// </summary>
/// <param name="input"></param>
/// <returns></returns>
private static string Md5Hash(string input)
{
MD5CryptoServiceProvider md5Hasher = new MD5CryptoServiceProvider();
byte[] data = md5Hasher.ComputeHash(Encoding.Default.GetBytes(input));
StringBuilder sBuilder = new StringBuilder();
for (int i = 0; i < data.Length; i++)
{
    sBuilder.Append(data[i].ToString("x2"));
}
return sBuilder.ToString();
}

 

 

 

本來我也以為System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile中的MD5和常用的一樣

可今天一試，結果有很大不同，
比如test,HashPasswordForStoringInConfigFile編碼成
C8059E2EC7419F590E79D7F1B774BFE6
而應該是098f6bcd4621d373cade4e832627b4f6

而且不同的機器不同的結果，有些結果正確
一看MSDN的解釋，原來是
Given a password and a string identifying the hash type, this routine produces a hash password suitable for storing in a configuration file.

為了和以前的代碼兼容和平台兼容，只好自己重新寫了MD5的算法，利用System.Security.Cryptography.MD5CryptoServiceProvider
代碼如下，大家執行一下就知道了，我就不多說了。

   <script language="C#" runat="server">
   string qswhMD5(string str){
     /************qiushuiwuhen(2002-9-27)***************/
     byte[] b=System.Text.Encoding.Default.GetBytes(str);
     b=new System.Security.Cryptography.MD5CryptoServiceProvider().ComputeHash(b);
     string ret="";
     for(int i=0;i<b.Length;i++)
      ret+=b[i].ToString("x").PadLeft(2,'0');
     return ret;
   }
   public void encryptString(Object sender, EventArgs e)
   {
     myMD5.Text=qswhMD5(txtClear.Text);
     MD5.Text =System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(txtClear.Text, "MD5") ;
   }
   </script>
   <body onload=document.all.txtClear.select();>
   <form runat="server">
    明文:<asp:Textbox id="txtClear" runat="server" />
    <asp:Button runat="server" text="Md5摘要" onClick="encryptString" ID="Button1" />
    <br/>通常用的 MD5:
    <br/><asp:label id="myMD5" runat="server" /> <br/>
    <br/>HashPasswordForStoringInConfigFile中的 MD5:
    <br/><asp:label id="MD5" runat="server" />
   </form>