is machine required for a web application with single page - asp.net

Question

I have created a web forms .net application which has jut got one page with four input fields.
I am storing the input parameters in the view state to be available between post backs.
This application is now deployed onto live server which is actually load balanced between two servers.
When I load the page, it works fine. But this application is going to be used by
10,000 users.
There is no machine key on the web.config file for this application. I read in a documentation when a application
is loaded on a web farm(when load balanced between two servers), a machine key is required to preserve
view state information.
So I tried to generated a machine key on my local host with the following settings
Encryption method: SHA1
Decryption method: auto
Validation key:
Automatically generate at runtime (unchecked)
Generate a unique key for each application (unchecked)
Decryption key:
Automatically generate at runtime (unchecked)
Generate a unique key for each application (unchecked)
I used the generated keys on the web.config of live server, but the application fails to load trying to load the login
page which is not my start page.
So my questions are:
1) Do I really need a machine key as the application is loading without it?
2) When thousands of users use the application page at the same time, is it alright without machine key?
3) If machine key is required, how is it generated and what encryption method, validation key and decryption key
parameters need to be used?

Answer 1

I dont know if you need a machine key. But here's how you generate one: Here is a little console program, which will create a machine key tag for your web.config. You can just copy the text from the console to your web.config like this:
<system.web>
...
<machineKey ... />
</system.web>
And the program. DISCLAIMER: Code not by me, I merely adapted it:
public class KeyCreator
{
const int VALIDATION_KEY_LENGTH = 24;
const int DECRYPTION_KEY_LENGTH = 64;
public static void Main(string[] args)
{
string decryptionKey = CreateKey(VALIDATION_KEY_LENGTH);
string validationKey = CreateKey(DECRYPTION_KEY_LENGTH);
Console.WriteLine("<machineKey validationKey=\"{0}\" decryptionKey=\"{1}\" validation=\"SHA1\"/>", validationKey, decryptionKey);
Console.ReadKey();
}
static string CreateKey(int numBytes)
{
RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
byte[] buff = new byte[numBytes];
rng.GetBytes(buff);
return BytesToHexString(buff);
}
static string BytesToHexString(byte[] bytes)
{
StringBuilder hexString = new StringBuilder(64);
for (int counter = 0; counter < bytes.Length; counter++)
{
hexString.Append(String.Format("{0:X2}", bytes[counter]));
}
return hexString.ToString();
}
}

Answer 2

I have generated the machine key as below on my local IIS and applied to the config file. I have then published that to live folder and it seems to be working fine.
Encryption method: SHA1
Decryption method: auto
Validation key:
Automatically generate at runtime (unchecked)
Generate a unique key for each application (unchecked)