Avoid description in viewstate

I have used viewstate in my application, as it is encripted and we could also decript the data now I want to avoid the decription how should I do that?

thanks in advance
raghul

Use a one way encryption. Like MD-5

how it can be decrypted my friend?
can you tell me the technique to decrypt it ?

It is one way encryption. One encryption value may have many decrypting values.