/**////
/// 用md5加密
///
/// 输入的数据
///
public static string MD5(string Sourcein)
...{
MD5CryptoServiceProvider MD5CSP = new MD5CryptoServiceProvider();
byte[] MD5Source = System.Text.Encoding.UTF8.GetBytes(Sourcein);
byte[] MD5Out = MD5CSP.ComputeHash(MD5Source);
return Convert.ToBase64String(MD5Out);
}

public static string md5(string str, int code)
...{
if (code == 16) //16位MD5加密（取32位加密的9~25字符）
...{
return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToLower().Substring(8, 16);
}

if (code == 32) //32位加密
...{
return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToLower();
}
return "00000000000000000000000000000000";
}